Update dependencies

67 files changed, 8011 insertions, 4551 deletions

diff --git a/vendor/google.golang.org/grpc/CONTRIBUTING.md b/vendor/google.golang.org/grpc/CONTRIBUTING.md
index a5c6e06..0863eb2 100644
--- a/vendor/google.golang.org/grpc/CONTRIBUTING.md
+++ b/vendor/google.golang.org/grpc/CONTRIBUTING.md
@@ -7,7 +7,7 @@ If you are new to github, please start by reading [Pull Request howto](https://h
 ## Legal requirements
 
 In order to protect both you and ourselves, you will need to sign the
-[Contributor License Agreement](https://cla.developers.google.com/clas).
+[Contributor License Agreement](https://identity.linuxfoundation.org/projects/cncf).
 
 ## Guidelines for Pull Requests
 How to get your contributions merged smoothly and quickly.
@@ -27,6 +27,10 @@ How to get your contributions merged smoothly and quickly.
 - Keep your PR up to date with upstream/master (if there are merge conflicts, we can't really merge your change).
  
 - **All tests need to be passing** before your change can be merged. We recommend you **run tests locally** before creating your PR to catch breakages early on.
+  - `make all` to test everything, OR
+  - `make vet` to catch vet errors
+  - `make test` to run the tests
+  - `make testrace` to run tests in race mode
 
 - Exceptions to the rules can be made if there's a compelling reason for doing so.
  
diff --git a/vendor/google.golang.org/grpc/Makefile b/vendor/google.golang.org/grpc/Makefile
index 39606b5..6f393a8 100644
--- a/vendor/google.golang.org/grpc/Makefile
+++ b/vendor/google.golang.org/grpc/Makefile
@@ -1,4 +1,4 @@
-all: test testrace
+all: vet test testrace
 
 deps:
 	go get -d -v google.golang.org/grpc/...
@@ -22,11 +22,14 @@ proto:
 	fi
 	go generate google.golang.org/grpc/...
 
+vet:
+	./vet.sh
+
 test: testdeps
-	go test -cpu 1,4 google.golang.org/grpc/...
+	go test -cpu 1,4 -timeout 5m google.golang.org/grpc/...
 
 testrace: testdeps
-	go test -race -cpu 1,4 google.golang.org/grpc/...
+	go test -race -cpu 1,4 -timeout 7m google.golang.org/grpc/...
 
 clean:
 	go clean -i google.golang.org/grpc/...
@@ -39,7 +42,7 @@ clean:
 	updatetestdeps \
 	build \
 	proto \
+	vet \
 	test \
 	testrace \
-	clean \
-	coverage
+	clean
diff --git a/vendor/google.golang.org/grpc/README.md b/vendor/google.golang.org/grpc/README.md
index 622a5dc..789adfd 100644
--- a/vendor/google.golang.org/grpc/README.md
+++ b/vendor/google.golang.org/grpc/README.md
@@ -1,6 +1,6 @@
 # gRPC-Go
 
-[![Build Status](https://travis-ci.org/grpc/grpc-go.svg)](https://travis-ci.org/grpc/grpc-go) [![GoDoc](https://godoc.org/google.golang.org/grpc?status.svg)](https://godoc.org/google.golang.org/grpc)
+[![Build Status](https://travis-ci.org/grpc/grpc-go.svg)](https://travis-ci.org/grpc/grpc-go) [![GoDoc](https://godoc.org/google.golang.org/grpc?status.svg)](https://godoc.org/google.golang.org/grpc) [![GoReportCard](https://goreportcard.com/badge/grpc/grpc-go)](https://goreportcard.com/report/github.com/grpc/grpc-go)
 
 The Go implementation of [gRPC](https://grpc.io/): A high performance, open source, general RPC framework that puts mobile and HTTP/2 first. For more information see the [gRPC Quick Start: Go](https://grpc.io/docs/quickstart/go.html) guide.
 
@@ -16,7 +16,7 @@ $ go get -u google.golang.org/grpc
 Prerequisites
 -------------
 
-This requires Go 1.7 or later.
+This requires Go 1.6 or later. Go 1.7 will be required soon.
 
 Constraints
 -----------
diff --git a/vendor/google.golang.org/grpc/backoff.go b/vendor/google.golang.org/grpc/backoff.go
index 090fbe8..fa31565 100644
--- a/vendor/google.golang.org/grpc/backoff.go
+++ b/vendor/google.golang.org/grpc/backoff.go
@@ -16,83 +16,23 @@
  *
  */
 
+// See internal/backoff package for the backoff implementation. This file is
+// kept for the exported types and API backward compatility.
+
 package grpc
 
 import (
-	"math/rand"
 	"time"
 )
 
 // DefaultBackoffConfig uses values specified for backoff in
 // https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md.
-var (
-	DefaultBackoffConfig = BackoffConfig{
-		MaxDelay:  120 * time.Second,
-		baseDelay: 1.0 * time.Second,
-		factor:    1.6,
-		jitter:    0.2,
-	}
-)
-
-// backoffStrategy defines the methodology for backing off after a grpc
-// connection failure.
-//
-// This is unexported until the gRPC project decides whether or not to allow
-// alternative backoff strategies. Once a decision is made, this type and its
-// method may be exported.
-type backoffStrategy interface {
-	// backoff returns the amount of time to wait before the next retry given
-	// the number of consecutive failures.
-	backoff(retries int) time.Duration
+var DefaultBackoffConfig = BackoffConfig{
+	MaxDelay: 120 * time.Second,
 }
 
 // BackoffConfig defines the parameters for the default gRPC backoff strategy.
 type BackoffConfig struct {
 	// MaxDelay is the upper bound of backoff delay.
 	MaxDelay time.Duration
-
-	// TODO(stevvooe): The following fields are not exported, as allowing
-	// changes would violate the current gRPC specification for backoff. If
-	// gRPC decides to allow more interesting backoff strategies, these fields
-	// may be opened up in the future.
-
-	// baseDelay is the amount of time to wait before retrying after the first
-	// failure.
-	baseDelay time.Duration
-
-	// factor is applied to the backoff after each retry.
-	factor float64
-
-	// jitter provides a range to randomize backoff delays.
-	jitter float64
-}
-
-func setDefaults(bc *BackoffConfig) {
-	md := bc.MaxDelay
-	*bc = DefaultBackoffConfig
-
-	if md > 0 {
-		bc.MaxDelay = md
-	}
-}
-
-func (bc BackoffConfig) backoff(retries int) time.Duration {
-	if retries == 0 {
-		return bc.baseDelay
-	}
-	backoff, max := float64(bc.baseDelay), float64(bc.MaxDelay)
-	for backoff < max && retries > 0 {
-		backoff *= bc.factor
-		retries--
-	}
-	if backoff > max {
-		backoff = max
-	}
-	// Randomize backoff delays so that if a cluster of requests start at
-	// the same time, they won't operate in lockstep.
-	backoff *= 1 + bc.jitter*(rand.Float64()*2-1)
-	if backoff < 0 {
-		return 0
-	}
-	return time.Duration(backoff)
 }
diff --git a/vendor/google.golang.org/grpc/balancer.go b/vendor/google.golang.org/grpc/balancer.go
index ab65049..e173016 100644
--- a/vendor/google.golang.org/grpc/balancer.go
+++ b/vendor/google.golang.org/grpc/balancer.go
@@ -28,10 +28,12 @@ import (
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/naming"
+	"google.golang.org/grpc/status"
 )
 
 // Address represents a server the client connects to.
-// This is the EXPERIMENTAL API and may be changed or extended in the future.
+//
+// Deprecated: please use package balancer.
 type Address struct {
 	// Addr is the server address on which a connection will be established.
 	Addr string
@@ -41,6 +43,8 @@ type Address struct {
 }
 
 // BalancerConfig specifies the configurations for Balancer.
+//
+// Deprecated: please use package balancer.
 type BalancerConfig struct {
 	// DialCreds is the transport credential the Balancer implementation can
 	// use to dial to a remote load balancer server. The Balancer implementations
@@ -53,7 +57,8 @@ type BalancerConfig struct {
 }
 
 // BalancerGetOptions configures a Get call.
-// This is the EXPERIMENTAL API and may be changed or extended in the future.
+//
+// Deprecated: please use package balancer.
 type BalancerGetOptions struct {
 	// BlockingWait specifies whether Get should block when there is no
 	// connected address.
@@ -61,7 +66,8 @@ type BalancerGetOptions struct {
 }
 
 // Balancer chooses network addresses for RPCs.
-// This is the EXPERIMENTAL API and may be changed or extended in the future.
+//
+// Deprecated: please use package balancer.
 type Balancer interface {
 	// Start does the initialization work to bootstrap a Balancer. For example,
 	// this function may start the name resolution and watch the updates. It will
@@ -134,6 +140,8 @@ func downErrorf(timeout, temporary bool, format string, a ...interface{}) downEr
 
 // RoundRobin returns a Balancer that selects addresses round-robin. It uses r to watch
 // the name resolution updates and updates the addresses available correspondingly.
+//
+// Deprecated: please use package balancer/roundrobin.
 func RoundRobin(r naming.Resolver) Balancer {
 	return &roundRobin{r: r}
 }
@@ -310,7 +318,7 @@ func (rr *roundRobin) Get(ctx context.Context, opts BalancerGetOptions) (addr Ad
 	if !opts.BlockingWait {
 		if len(rr.addrs) == 0 {
 			rr.mu.Unlock()
-			err = Errorf(codes.Unavailable, "there is no address available")
+			err = status.Errorf(codes.Unavailable, "there is no address available")
 			return
 		}
 		// Returns the next addr on rr.addrs for failfast RPCs.
diff --git a/vendor/google.golang.org/grpc/balancer/balancer.go b/vendor/google.golang.org/grpc/balancer/balancer.go
index 84e10b6..f9d83c2 100644
--- a/vendor/google.golang.org/grpc/balancer/balancer.go
+++ b/vendor/google.golang.org/grpc/balancer/balancer.go
@@ -23,6 +23,7 @@ package balancer
 import (
 	"errors"
 	"net"
+	"strings"
 
 	"golang.org/x/net/context"
 	"google.golang.org/grpc/connectivity"
@@ -33,24 +34,26 @@ import (
 var (
 	// m is a map from name to balancer builder.
 	m = make(map[string]Builder)
-	// defaultBuilder is the default balancer to use.
-	defaultBuilder Builder // TODO(bar) install pickfirst as default.
 )
 
-// Register registers the balancer builder to the balancer map.
-// b.Name will be used as the name registered with this builder.
+// Register registers the balancer builder to the balancer map. b.Name
+// (lowercased) will be used as the name registered with this builder.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. If multiple Balancers are
+// registered with the same name, the one registered last will take effect.
 func Register(b Builder) {
-	m[b.Name()] = b
+	m[strings.ToLower(b.Name())] = b
 }
 
 // Get returns the resolver builder registered with the given name.
-// If no builder is register with the name, the default pickfirst will
-// be used.
+// Note that the compare is done in a case-insenstive fashion.
+// If no builder is register with the name, nil will be returned.
 func Get(name string) Builder {
-	if b, ok := m[name]; ok {
+	if b, ok := m[strings.ToLower(name)]; ok {
 		return b
 	}
-	return defaultBuilder
+	return nil
 }
 
 // SubConn represents a gRPC sub connection.
@@ -66,6 +69,11 @@ func Get(name string) Builder {
 // When the connection encounters an error, it will reconnect immediately.
 // When the connection becomes IDLE, it will not reconnect unless Connect is
 // called.
+//
+// This interface is to be implemented by gRPC. Users should not need a
+// brand new implementation of this interface. For the situations like
+// testing, the new implementation should embed this interface. This allows
+// gRPC to add new methods to this interface.
 type SubConn interface {
 	// UpdateAddresses updates the addresses used in this SubConn.
 	// gRPC checks if currently-connected address is still in the new list.
@@ -83,6 +91,11 @@ type SubConn interface {
 type NewSubConnOptions struct{}
 
 // ClientConn represents a gRPC ClientConn.
+//
+// This interface is to be implemented by gRPC. Users should not need a
+// brand new implementation of this interface. For the situations like
+// testing, the new implementation should embed this interface. This allows
+// gRPC to add new methods to this interface.
 type ClientConn interface {
 	// NewSubConn is called by balancer to create a new SubConn.
 	// It doesn't block and wait for the connections to be established.
@@ -99,6 +112,9 @@ type ClientConn interface {
 	// on the new picker to pick new SubConn.
 	UpdateBalancerState(s connectivity.State, p Picker)
 
+	// ResolveNow is called by balancer to notify gRPC to do a name resolving.
+	ResolveNow(resolver.ResolveNowOption)
+
 	// Target returns the dial target for this ClientConn.
 	Target() string
 }
@@ -113,6 +129,8 @@ type BuildOptions struct {
 	// to a remote load balancer server. The Balancer implementations
 	// can ignore this if it doesn't need to talk to remote balancer.
 	Dialer func(context.Context, string) (net.Conn, error)
+	// ChannelzParentID is the entity parent's channelz unique identification number.
+	ChannelzParentID int64
 }
 
 // Builder creates a balancer.
@@ -131,6 +149,10 @@ type PickOptions struct{}
 type DoneInfo struct {
 	// Err is the rpc error the RPC finished with. It could be nil.
 	Err error
+	// BytesSent indicates if any bytes have been sent to the server.
+	BytesSent bool
+	// BytesReceived indicates if any byte has been received from the server.
+	BytesReceived bool
 }
 
 var (
@@ -143,7 +165,7 @@ var (
 )
 
 // Picker is used by gRPC to pick a SubConn to send an RPC.
-// Balancer is expected to generate a new picker from its snapshot everytime its
+// Balancer is expected to generate a new picker from its snapshot every time its
 // internal state has changed.
 //
 // The pickers used by gRPC can be updated by ClientConn.UpdateBalancerState().
@@ -161,7 +183,7 @@ type Picker interface {
 	// If a SubConn is returned:
 	// - If it is READY, gRPC will send the RPC on it;
 	// - If it is not ready, or becomes not ready after it's returned, gRPC will block
-	//   this call until a new picker is updated and will call pick on the new picker.
+	//   until UpdateBalancerState() is called and will call pick on the new picker.
 	//
 	// If the returned error is not nil:
 	// - If the error is ErrNoSubConnAvailable, gRPC will block until UpdateBalancerState()
@@ -204,3 +226,45 @@ type Balancer interface {
 	// ClientConn.RemoveSubConn for its existing SubConns.
 	Close()
 }
+
+// ConnectivityStateEvaluator takes the connectivity states of multiple SubConns
+// and returns one aggregated connectivity state.
+//
+// It's not thread safe.
+type ConnectivityStateEvaluator struct {
+	numReady            uint64 // Number of addrConns in ready state.
+	numConnecting       uint64 // Number of addrConns in connecting state.
+	numTransientFailure uint64 // Number of addrConns in transientFailure.
+}
+
+// RecordTransition records state change happening in subConn and based on that
+// it evaluates what aggregated state should be.
+//
+//  - If at least one SubConn in Ready, the aggregated state is Ready;
+//  - Else if at least one SubConn in Connecting, the aggregated state is Connecting;
+//  - Else the aggregated state is TransientFailure.
+//
+// Idle and Shutdown are not considered.
+func (cse *ConnectivityStateEvaluator) RecordTransition(oldState, newState connectivity.State) connectivity.State {
+	// Update counters.
+	for idx, state := range []connectivity.State{oldState, newState} {
+		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
+		switch state {
+		case connectivity.Ready:
+			cse.numReady += updateVal
+		case connectivity.Connecting:
+			cse.numConnecting += updateVal
+		case connectivity.TransientFailure:
+			cse.numTransientFailure += updateVal
+		}
+	}
+
+	// Evaluate.
+	if cse.numReady > 0 {
+		return connectivity.Ready
+	}
+	if cse.numConnecting > 0 {
+		return connectivity.Connecting
+	}
+	return connectivity.TransientFailure
+}
diff --git a/vendor/google.golang.org/grpc/balancer/base/balancer.go b/vendor/google.golang.org/grpc/balancer/base/balancer.go
new file mode 100644
index 0000000..23d1351
--- /dev/null
+++ b/vendor/google.golang.org/grpc/balancer/base/balancer.go
@@ -0,0 +1,208 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package base
+
+import (
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+type baseBuilder struct {
+	name          string
+	pickerBuilder PickerBuilder
+}
+
+func (bb *baseBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer {
+	return &baseBalancer{
+		cc:            cc,
+		pickerBuilder: bb.pickerBuilder,
+
+		subConns: make(map[resolver.Address]balancer.SubConn),
+		scStates: make(map[balancer.SubConn]connectivity.State),
+		csEvltr:  &connectivityStateEvaluator{},
+		// Initialize picker to a picker that always return
+		// ErrNoSubConnAvailable, because when state of a SubConn changes, we
+		// may call UpdateBalancerState with this picker.
+		picker: NewErrPicker(balancer.ErrNoSubConnAvailable),
+	}
+}
+
+func (bb *baseBuilder) Name() string {
+	return bb.name
+}
+
+type baseBalancer struct {
+	cc            balancer.ClientConn
+	pickerBuilder PickerBuilder
+
+	csEvltr *connectivityStateEvaluator
+	state   connectivity.State
+
+	subConns map[resolver.Address]balancer.SubConn
+	scStates map[balancer.SubConn]connectivity.State
+	picker   balancer.Picker
+}
+
+func (b *baseBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
+	if err != nil {
+		grpclog.Infof("base.baseBalancer: HandleResolvedAddrs called with error %v", err)
+		return
+	}
+	grpclog.Infoln("base.baseBalancer: got new resolved addresses: ", addrs)
+	// addrsSet is the set converted from addrs, it's used for quick lookup of an address.
+	addrsSet := make(map[resolver.Address]struct{})
+	for _, a := range addrs {
+		addrsSet[a] = struct{}{}
+		if _, ok := b.subConns[a]; !ok {
+			// a is a new address (not existing in b.subConns).
+			sc, err := b.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{})
+			if err != nil {
+				grpclog.Warningf("base.baseBalancer: failed to create new SubConn: %v", err)
+				continue
+			}
+			b.subConns[a] = sc
+			b.scStates[sc] = connectivity.Idle
+			sc.Connect()
+		}
+	}
+	for a, sc := range b.subConns {
+		// a was removed by resolver.
+		if _, ok := addrsSet[a]; !ok {
+			b.cc.RemoveSubConn(sc)
+			delete(b.subConns, a)
+			// Keep the state of this sc in b.scStates until sc's state becomes Shutdown.
+			// The entry will be deleted in HandleSubConnStateChange.
+		}
+	}
+}
+
+// regeneratePicker takes a snapshot of the balancer, and generates a picker
+// from it. The picker is
+//  - errPicker with ErrTransientFailure if the balancer is in TransientFailure,
+//  - built by the pickerBuilder with all READY SubConns otherwise.
+func (b *baseBalancer) regeneratePicker() {
+	if b.state == connectivity.TransientFailure {
+		b.picker = NewErrPicker(balancer.ErrTransientFailure)
+		return
+	}
+	readySCs := make(map[resolver.Address]balancer.SubConn)
+
+	// Filter out all ready SCs from full subConn map.
+	for addr, sc := range b.subConns {
+		if st, ok := b.scStates[sc]; ok && st == connectivity.Ready {
+			readySCs[addr] = sc
+		}
+	}
+	b.picker = b.pickerBuilder.Build(readySCs)
+}
+
+func (b *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+	grpclog.Infof("base.baseBalancer: handle SubConn state change: %p, %v", sc, s)
+	oldS, ok := b.scStates[sc]
+	if !ok {
+		grpclog.Infof("base.baseBalancer: got state changes for an unknown SubConn: %p, %v", sc, s)
+		return
+	}
+	b.scStates[sc] = s
+	switch s {
+	case connectivity.Idle:
+		sc.Connect()
+	case connectivity.Shutdown:
+		// When an address was removed by resolver, b called RemoveSubConn but
+		// kept the sc's state in scStates. Remove state for this sc here.
+		delete(b.scStates, sc)
+	}
+
+	oldAggrState := b.state
+	b.state = b.csEvltr.recordTransition(oldS, s)
+
+	// Regenerate picker when one of the following happens:
+	//  - this sc became ready from not-ready
+	//  - this sc became not-ready from ready
+	//  - the aggregated state of balancer became TransientFailure from non-TransientFailure
+	//  - the aggregated state of balancer became non-TransientFailure from TransientFailure
+	if (s == connectivity.Ready) != (oldS == connectivity.Ready) ||
+		(b.state == connectivity.TransientFailure) != (oldAggrState == connectivity.TransientFailure) {
+		b.regeneratePicker()
+	}
+
+	b.cc.UpdateBalancerState(b.state, b.picker)
+}
+
+// Close is a nop because base balancer doesn't have internal state to clean up,
+// and it doesn't need to call RemoveSubConn for the SubConns.
+func (b *baseBalancer) Close() {
+}
+
+// NewErrPicker returns a picker that always returns err on Pick().
+func NewErrPicker(err error) balancer.Picker {
+	return &errPicker{err: err}
+}
+
+type errPicker struct {
+	err error // Pick() always returns this err.
+}
+
+func (p *errPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	return nil, nil, p.err
+}
+
+// connectivityStateEvaluator gets updated by addrConns when their
+// states transition, based on which it evaluates the state of
+// ClientConn.
+type connectivityStateEvaluator struct {
+	numReady            uint64 // Number of addrConns in ready state.
+	numConnecting       uint64 // Number of addrConns in connecting state.
+	numTransientFailure uint64 // Number of addrConns in transientFailure.
+}
+
+// recordTransition records state change happening in every subConn and based on
+// that it evaluates what aggregated state should be.
+// It can only transition between Ready, Connecting and TransientFailure. Other states,
+// Idle and Shutdown are transitioned into by ClientConn; in the beginning of the connection
+// before any subConn is created ClientConn is in idle state. In the end when ClientConn
+// closes it is in Shutdown state.
+//
+// recordTransition should only be called synchronously from the same goroutine.
+func (cse *connectivityStateEvaluator) recordTransition(oldState, newState connectivity.State) connectivity.State {
+	// Update counters.
+	for idx, state := range []connectivity.State{oldState, newState} {
+		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
+		switch state {
+		case connectivity.Ready:
+			cse.numReady += updateVal
+		case connectivity.Connecting:
+			cse.numConnecting += updateVal
+		case connectivity.TransientFailure:
+			cse.numTransientFailure += updateVal
+		}
+	}
+
+	// Evaluate.
+	if cse.numReady > 0 {
+		return connectivity.Ready
+	}
+	if cse.numConnecting > 0 {
+		return connectivity.Connecting
+	}
+	return connectivity.TransientFailure
+}
diff --git a/vendor/google.golang.org/grpc/balancer/base/base.go b/vendor/google.golang.org/grpc/balancer/base/base.go
new file mode 100644
index 0000000..012ace2
--- /dev/null
+++ b/vendor/google.golang.org/grpc/balancer/base/base.go
@@ -0,0 +1,52 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package base defines a balancer base that can be used to build balancers with
+// different picking algorithms.
+//
+// The base balancer creates a new SubConn for each resolved address. The
+// provided picker will only be notified about READY SubConns.
+//
+// This package is the base of round_robin balancer, its purpose is to be used
+// to build round_robin like balancers with complex picking algorithms.
+// Balancers with more complicated logic should try to implement a balancer
+// builder from scratch.
+//
+// All APIs in this package are experimental.
+package base
+
+import (
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/resolver"
+)
+
+// PickerBuilder creates balancer.Picker.
+type PickerBuilder interface {
+	// Build takes a slice of ready SubConns, and returns a picker that will be
+	// used by gRPC to pick a SubConn.
+	Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker
+}
+
+// NewBalancerBuilder returns a balancer builder. The balancers
+// built by this builder will use the picker builder to build pickers.
+func NewBalancerBuilder(name string, pb PickerBuilder) balancer.Builder {
+	return &baseBuilder{
+		name:          name,
+		pickerBuilder: pb,
+	}
+}
diff --git a/vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go b/vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go
new file mode 100644
index 0000000..2eda0a1
--- /dev/null
+++ b/vendor/google.golang.org/grpc/balancer/roundrobin/roundrobin.go
@@ -0,0 +1,79 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package roundrobin defines a roundrobin balancer. Roundrobin balancer is
+// installed as one of the default balancers in gRPC, users don't need to
+// explicitly install this balancer.
+package roundrobin
+
+import (
+	"sync"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/balancer/base"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/resolver"
+)
+
+// Name is the name of round_robin balancer.
+const Name = "round_robin"
+
+// newBuilder creates a new roundrobin balancer builder.
+func newBuilder() balancer.Builder {
+	return base.NewBalancerBuilder(Name, &rrPickerBuilder{})
+}
+
+func init() {
+	balancer.Register(newBuilder())
+}
+
+type rrPickerBuilder struct{}
+
+func (*rrPickerBuilder) Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker {
+	grpclog.Infof("roundrobinPicker: newPicker called with readySCs: %v", readySCs)
+	var scs []balancer.SubConn
+	for _, sc := range readySCs {
+		scs = append(scs, sc)
+	}
+	return &rrPicker{
+		subConns: scs,
+	}
+}
+
+type rrPicker struct {
+	// subConns is the snapshot of the roundrobin balancer when this picker was
+	// created. The slice is immutable. Each Get() will do a round robin
+	// selection from it and return the selected SubConn.
+	subConns []balancer.SubConn
+
+	mu   sync.Mutex
+	next int
+}
+
+func (p *rrPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+	if len(p.subConns) <= 0 {
+		return nil, nil, balancer.ErrNoSubConnAvailable
+	}
+
+	p.mu.Lock()
+	sc := p.subConns[p.next]
+	p.next = (p.next + 1) % len(p.subConns)
+	p.mu.Unlock()
+	return sc, nil, nil
+}
diff --git a/vendor/google.golang.org/grpc/balancer_conn_wrappers.go b/vendor/google.golang.org/grpc/balancer_conn_wrappers.go
index e4a95fd..c23f817 100644
--- a/vendor/google.golang.org/grpc/balancer_conn_wrappers.go
+++ b/vendor/google.golang.org/grpc/balancer_conn_wrappers.go
@@ -19,6 +19,7 @@
 package grpc
 
 import (
+	"fmt"
 	"sync"
 
 	"google.golang.org/grpc/balancer"
@@ -73,7 +74,7 @@ func (b *scStateUpdateBuffer) load() {
 	}
 }
 
-// get returns the channel that receives a recvMsg in the buffer.
+// get returns the channel that the scStateUpdate will be sent to.
 //
 // Upon receiving, the caller should call load to send another
 // scStateChangeTuple onto the channel if there is any.
@@ -96,6 +97,9 @@ type ccBalancerWrapper struct {
 	stateChangeQueue *scStateUpdateBuffer
 	resolverUpdateCh chan *resolverUpdate
 	done             chan struct{}
+
+	mu       sync.Mutex
+	subConns map[*acBalancerWrapper]struct{}
 }
 
 func newCCBalancerWrapper(cc *ClientConn, b balancer.Builder, bopts balancer.BuildOptions) *ccBalancerWrapper {
@@ -104,21 +108,34 @@ func newCCBalancerWrapper(cc *ClientConn, b balancer.Builder, bopts balancer.Bui
 		stateChangeQueue: newSCStateUpdateBuffer(),
 		resolverUpdateCh: make(chan *resolverUpdate, 1),
 		done:             make(chan struct{}),
+		subConns:         make(map[*acBalancerWrapper]struct{}),
 	}
 	go ccb.watcher()
 	ccb.balancer = b.Build(ccb, bopts)
 	return ccb
 }
 
-// watcher balancer functions sequencially, so the balancer can be implemeneted
+// watcher balancer functions sequentially, so the balancer can be implemented
 // lock-free.
 func (ccb *ccBalancerWrapper) watcher() {
 	for {
 		select {
 		case t := <-ccb.stateChangeQueue.get():
 			ccb.stateChangeQueue.load()
+			select {
+			case <-ccb.done:
+				ccb.balancer.Close()
+				return
+			default:
+			}
 			ccb.balancer.HandleSubConnStateChange(t.sc, t.state)
 		case t := <-ccb.resolverUpdateCh:
+			select {
+			case <-ccb.done:
+				ccb.balancer.Close()
+				return
+			default:
+			}
 			ccb.balancer.HandleResolvedAddrs(t.addrs, t.err)
 		case <-ccb.done:
 		}
@@ -126,6 +143,13 @@ func (ccb *ccBalancerWrapper) watcher() {
 		select {
 		case <-ccb.done:
 			ccb.balancer.Close()
+			ccb.mu.Lock()
+			scs := ccb.subConns
+			ccb.subConns = nil
+			ccb.mu.Unlock()
+			for acbw := range scs {
+				ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
+			}
 			return
 		default:
 		}
@@ -165,31 +189,54 @@ func (ccb *ccBalancerWrapper) handleResolvedAddrs(addrs []resolver.Address, err
 }
 
 func (ccb *ccBalancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) {
-	grpclog.Infof("ccBalancerWrapper: new subconn: %v", addrs)
+	if len(addrs) <= 0 {
+		return nil, fmt.Errorf("grpc: cannot create SubConn with empty address list")
+	}
+	ccb.mu.Lock()
+	defer ccb.mu.Unlock()
+	if ccb.subConns == nil {
+		return nil, fmt.Errorf("grpc: ClientConn balancer wrapper was closed")
+	}
 	ac, err := ccb.cc.newAddrConn(addrs)
 	if err != nil {
 		return nil, err
 	}
 	acbw := &acBalancerWrapper{ac: ac}
+	acbw.ac.mu.Lock()
 	ac.acbw = acbw
+	acbw.ac.mu.Unlock()
+	ccb.subConns[acbw] = struct{}{}
 	return acbw, nil
 }
 
 func (ccb *ccBalancerWrapper) RemoveSubConn(sc balancer.SubConn) {
-	grpclog.Infof("ccBalancerWrapper: removing subconn")
 	acbw, ok := sc.(*acBalancerWrapper)
 	if !ok {
 		return
 	}
+	ccb.mu.Lock()
+	defer ccb.mu.Unlock()
+	if ccb.subConns == nil {
+		return
+	}
+	delete(ccb.subConns, acbw)
 	ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
 }
 
 func (ccb *ccBalancerWrapper) UpdateBalancerState(s connectivity.State, p balancer.Picker) {
-	grpclog.Infof("ccBalancerWrapper: updating state and picker called by balancer: %v, %p", s, p)
+	ccb.mu.Lock()
+	defer ccb.mu.Unlock()
+	if ccb.subConns == nil {
+		return
+	}
 	ccb.cc.csMgr.updateState(s)
 	ccb.cc.blockingpicker.updatePicker(p)
 }
 
+func (ccb *ccBalancerWrapper) ResolveNow(o resolver.ResolveNowOption) {
+	ccb.cc.resolveNow(o)
+}
+
 func (ccb *ccBalancerWrapper) Target() string {
 	return ccb.cc.target
 }
@@ -202,9 +249,12 @@ type acBalancerWrapper struct {
 }
 
 func (acbw *acBalancerWrapper) UpdateAddresses(addrs []resolver.Address) {
-	grpclog.Infof("acBalancerWrapper: UpdateAddresses called with %v", addrs)
 	acbw.mu.Lock()
 	defer acbw.mu.Unlock()
+	if len(addrs) <= 0 {
+		acbw.ac.tearDown(errConnDrain)
+		return
+	}
 	if !acbw.ac.tryUpdateAddrs(addrs) {
 		cc := acbw.ac.cc
 		acbw.ac.mu.Lock()
@@ -228,9 +278,11 @@ func (acbw *acBalancerWrapper) UpdateAddresses(addrs []resolver.Address) {
 			return
 		}
 		acbw.ac = ac
+		ac.mu.Lock()
 		ac.acbw = acbw
+		ac.mu.Unlock()
 		if acState != connectivity.Idle {
-			ac.connect(false)
+			ac.connect()
 		}
 	}
 }
@@ -238,7 +290,7 @@ func (acbw *acBalancerWrapper) UpdateAddresses(addrs []resolver.Address) {
 func (acbw *acBalancerWrapper) Connect() {
 	acbw.mu.Lock()
 	defer acbw.mu.Unlock()
-	acbw.ac.connect(false)
+	acbw.ac.connect()
 }
 
 func (acbw *acBalancerWrapper) getAddrConn() *addrConn {
diff --git a/vendor/google.golang.org/grpc/balancer_v1_wrapper.go b/vendor/google.golang.org/grpc/balancer_v1_wrapper.go
index 9d06160..e0ce32c 100644
--- a/vendor/google.golang.org/grpc/balancer_v1_wrapper.go
+++ b/vendor/google.golang.org/grpc/balancer_v1_wrapper.go
@@ -19,6 +19,7 @@
 package grpc
 
 import (
+	"strings"
 	"sync"
 
 	"golang.org/x/net/context"
@@ -27,6 +28,7 @@ import (
 	"google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/resolver"
+	"google.golang.org/grpc/status"
 )
 
 type balancerWrapperBuilder struct {
@@ -34,20 +36,27 @@ type balancerWrapperBuilder struct {
 }
 
 func (bwb *balancerWrapperBuilder) Build(cc balancer.ClientConn, opts balancer.BuildOptions) balancer.Balancer {
-	bwb.b.Start(cc.Target(), BalancerConfig{
+	targetAddr := cc.Target()
+	targetSplitted := strings.Split(targetAddr, ":///")
+	if len(targetSplitted) >= 2 {
+		targetAddr = targetSplitted[1]
+	}
+
+	bwb.b.Start(targetAddr, BalancerConfig{
 		DialCreds: opts.DialCreds,
 		Dialer:    opts.Dialer,
 	})
 	_, pickfirst := bwb.b.(*pickFirst)
 	bw := &balancerWrapper{
-		balancer:  bwb.b,
-		pickfirst: pickfirst,
-		cc:        cc,
-		startCh:   make(chan struct{}),
-		conns:     make(map[resolver.Address]balancer.SubConn),
-		connSt:    make(map[balancer.SubConn]*scState),
-		csEvltr:   &connectivityStateEvaluator{},
-		state:     connectivity.Idle,
+		balancer:   bwb.b,
+		pickfirst:  pickfirst,
+		cc:         cc,
+		targetAddr: targetAddr,
+		startCh:    make(chan struct{}),
+		conns:      make(map[resolver.Address]balancer.SubConn),
+		connSt:     make(map[balancer.SubConn]*scState),
+		csEvltr:    &balancer.ConnectivityStateEvaluator{},
+		state:      connectivity.Idle,
 	}
 	cc.UpdateBalancerState(connectivity.Idle, bw)
 	go bw.lbWatcher()
@@ -68,11 +77,8 @@ type balancerWrapper struct {
 	balancer  Balancer // The v1 balancer.
 	pickfirst bool
 
-	cc balancer.ClientConn
-
-	// To aggregate the connectivity state.
-	csEvltr *connectivityStateEvaluator
-	state   connectivity.State
+	cc         balancer.ClientConn
+	targetAddr string // Target without the scheme.
 
 	mu     sync.Mutex
 	conns  map[resolver.Address]balancer.SubConn
@@ -82,18 +88,21 @@ type balancerWrapper struct {
 	// - NewSubConn is created, cc wants to notify balancer of state changes;
 	// - Build hasn't return, cc doesn't have access to balancer.
 	startCh chan struct{}
+
+	// To aggregate the connectivity state.
+	csEvltr *balancer.ConnectivityStateEvaluator
+	state   connectivity.State
 }
 
 // lbWatcher watches the Notify channel of the balancer and manages
 // connections accordingly.
 func (bw *balancerWrapper) lbWatcher() {
 	<-bw.startCh
-	grpclog.Infof("balancerWrapper: is pickfirst: %v\n", bw.pickfirst)
 	notifyCh := bw.balancer.Notify()
 	if notifyCh == nil {
 		// There's no resolver in the balancer. Connect directly.
 		a := resolver.Address{
-			Addr: bw.cc.Target(),
+			Addr: bw.targetAddr,
 			Type: resolver.Backend,
 		}
 		sc, err := bw.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{})
@@ -103,7 +112,7 @@ func (bw *balancerWrapper) lbWatcher() {
 			bw.mu.Lock()
 			bw.conns[a] = sc
 			bw.connSt[sc] = &scState{
-				addr: Address{Addr: bw.cc.Target()},
+				addr: Address{Addr: bw.targetAddr},
 				s:    connectivity.Idle,
 			}
 			bw.mu.Unlock()
@@ -165,10 +174,10 @@ func (bw *balancerWrapper) lbWatcher() {
 					sc.Connect()
 				}
 			} else {
-				oldSC.UpdateAddresses(newAddrs)
 				bw.mu.Lock()
 				bw.connSt[oldSC].addr = addrs[0]
 				bw.mu.Unlock()
+				oldSC.UpdateAddresses(newAddrs)
 			}
 		} else {
 			var (
@@ -221,7 +230,6 @@ func (bw *balancerWrapper) lbWatcher() {
 }
 
 func (bw *balancerWrapper) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
-	grpclog.Infof("balancerWrapper: handle subconn state change: %p, %v", sc, s)
 	bw.mu.Lock()
 	defer bw.mu.Unlock()
 	scSt, ok := bw.connSt[sc]
@@ -240,7 +248,7 @@ func (bw *balancerWrapper) HandleSubConnStateChange(sc balancer.SubConn, s conne
 			scSt.down(errConnClosing)
 		}
 	}
-	sa := bw.csEvltr.recordTransition(oldS, s)
+	sa := bw.csEvltr.RecordTransition(oldS, s)
 	if bw.state != sa {
 		bw.state = sa
 	}
@@ -249,7 +257,6 @@ func (bw *balancerWrapper) HandleSubConnStateChange(sc balancer.SubConn, s conne
 		// Remove state for this sc.
 		delete(bw.connSt, sc)
 	}
-	return
 }
 
 func (bw *balancerWrapper) HandleResolvedAddrs([]resolver.Address, error) {
@@ -262,7 +269,6 @@ func (bw *balancerWrapper) HandleResolvedAddrs([]resolver.Address, error) {
 	}
 	// There should be a resolver inside the balancer.
 	// All updates here, if any, are ignored.
-	return
 }
 
 func (bw *balancerWrapper) Close() {
@@ -274,7 +280,6 @@ func (bw *balancerWrapper) Close() {
 		close(bw.startCh)
 	}
 	bw.balancer.Close()
-	return
 }
 
 // The picker is the balancerWrapper itself.
@@ -310,58 +315,14 @@ func (bw *balancerWrapper) Pick(ctx context.Context, opts balancer.PickOptions)
 			Metadata:   a.Metadata,
 		}]
 		if !ok && failfast {
-			return nil, nil, Errorf(codes.Unavailable, "there is no connection available")
+			return nil, nil, status.Errorf(codes.Unavailable, "there is no connection available")
 		}
 		if s, ok := bw.connSt[sc]; failfast && (!ok || s.s != connectivity.Ready) {
 			// If the returned sc is not ready and RPC is failfast,
 			// return error, and this RPC will fail.
-			return nil, nil, Errorf(codes.Unavailable, "there is no connection available")
+			return nil, nil, status.Errorf(codes.Unavailable, "there is no connection available")
 		}
 	}
 
 	return sc, done, nil
 }
-
-// connectivityStateEvaluator gets updated by addrConns when their
-// states transition, based on which it evaluates the state of
-// ClientConn.
-type connectivityStateEvaluator struct {
-	mu                  sync.Mutex
-	numReady            uint64 // Number of addrConns in ready state.
-	numConnecting       uint64 // Number of addrConns in connecting state.
-	numTransientFailure uint64 // Number of addrConns in transientFailure.
-}
-
-// recordTransition records state change happening in every subConn and based on
-// that it evaluates what aggregated state should be.
-// It can only transition between Ready, Connecting and TransientFailure. Other states,
-// Idle and Shutdown are transitioned into by ClientConn; in the beginning of the connection
-// before any subConn is created ClientConn is in idle state. In the end when ClientConn
-// closes it is in Shutdown state.
-// TODO Note that in later releases, a ClientConn with no activity will be put into an Idle state.
-func (cse *connectivityStateEvaluator) recordTransition(oldState, newState connectivity.State) connectivity.State {
-	cse.mu.Lock()
-	defer cse.mu.Unlock()
-
-	// Update counters.
-	for idx, state := range []connectivity.State{oldState, newState} {
-		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
-		switch state {
-		case connectivity.Ready:
-			cse.numReady += updateVal
-		case connectivity.Connecting:
-			cse.numConnecting += updateVal
-		case connectivity.TransientFailure:
-			cse.numTransientFailure += updateVal
-		}
-	}
-
-	// Evaluate.
-	if cse.numReady > 0 {
-		return connectivity.Ready
-	}
-	if cse.numConnecting > 0 {
-		return connectivity.Connecting
-	}
-	return connectivity.TransientFailure
-}
diff --git a/vendor/google.golang.org/grpc/call.go b/vendor/google.golang.org/grpc/call.go
index 1ef2507..f73b7d5 100644
--- a/vendor/google.golang.org/grpc/call.go
+++ b/vendor/google.golang.org/grpc/call.go
@@ -19,289 +19,75 @@
 package grpc
 
 import (
-	"bytes"
-	"io"
-	"time"
-
 	"golang.org/x/net/context"
-	"golang.org/x/net/trace"
-	"google.golang.org/grpc/balancer"
-	"google.golang.org/grpc/codes"
-	"google.golang.org/grpc/peer"
-	"google.golang.org/grpc/stats"
-	"google.golang.org/grpc/status"
-	"google.golang.org/grpc/transport"
 )
 
-// recvResponse receives and parses an RPC response.
-// On error, it returns the error and indicates whether the call should be retried.
+// Invoke sends the RPC request on the wire and returns after response is
+// received.  This is typically called by generated code.
 //
-// TODO(zhaoq): Check whether the received message sequence is valid.
-// TODO ctx is used for stats collection and processing. It is the context passed from the application.
-func recvResponse(ctx context.Context, dopts dialOptions, t transport.ClientTransport, c *callInfo, stream *transport.Stream, reply interface{}) (err error) {
-	// Try to acquire header metadata from the server if there is any.
-	defer func() {
-		if err != nil {
-			if _, ok := err.(transport.ConnectionError); !ok {
-				t.CloseStream(stream, err)
-			}
-		}
-	}()
-	c.headerMD, err = stream.Header()
-	if err != nil {
-		return
-	}
-	p := &parser{r: stream}
-	var inPayload *stats.InPayload
-	if dopts.copts.StatsHandler != nil {
-		inPayload = &stats.InPayload{
-			Client: true,
-		}
-	}
-	for {
-		if c.maxReceiveMessageSize == nil {
-			return Errorf(codes.Internal, "callInfo maxReceiveMessageSize field uninitialized(nil)")
-		}
-		if err = recv(p, dopts.codec, stream, dopts.dc, reply, *c.maxReceiveMessageSize, inPayload); err != nil {
-			if err == io.EOF {
-				break
-			}
-			return
-		}
-	}
-	if inPayload != nil && err == io.EOF && stream.Status().Code() == codes.OK {
-		// TODO in the current implementation, inTrailer may be handled before inPayload in some cases.
-		// Fix the order if necessary.
-		dopts.copts.StatsHandler.HandleRPC(ctx, inPayload)
-	}
-	c.trailerMD = stream.Trailer()
-	return nil
-}
+// All errors returned by Invoke are compatible with the status package.
+func (cc *ClientConn) Invoke(ctx context.Context, method string, args, reply interface{}, opts ...CallOption) error {
+	// allow interceptor to see all applicable call options, which means those
+	// configured as defaults from dial option as well as per-call options
+	opts = combine(cc.dopts.callOptions, opts)
 
-// sendRequest writes out various information of an RPC such as Context and Message.
-func sendRequest(ctx context.Context, dopts dialOptions, compressor Compressor, c *callInfo, callHdr *transport.CallHdr, stream *transport.Stream, t transport.ClientTransport, args interface{}, opts *transport.Options) (err error) {
-	defer func() {
-		if err != nil {
-			// If err is connection error, t will be closed, no need to close stream here.
-			if _, ok := err.(transport.ConnectionError); !ok {
-				t.CloseStream(stream, err)
-			}
-		}
-	}()
-	var (
-		cbuf       *bytes.Buffer
-		outPayload *stats.OutPayload
-	)
-	if compressor != nil {
-		cbuf = new(bytes.Buffer)
-	}
-	if dopts.copts.StatsHandler != nil {
-		outPayload = &stats.OutPayload{
-			Client: true,
-		}
-	}
-	hdr, data, err := encode(dopts.codec, args, compressor, cbuf, outPayload)
-	if err != nil {
-		return err
-	}
-	if c.maxSendMessageSize == nil {
-		return Errorf(codes.Internal, "callInfo maxSendMessageSize field uninitialized(nil)")
-	}
-	if len(data) > *c.maxSendMessageSize {
-		return Errorf(codes.ResourceExhausted, "grpc: trying to send message larger than max (%d vs. %d)", len(data), *c.maxSendMessageSize)
-	}
-	err = t.Write(stream, hdr, data, opts)
-	if err == nil && outPayload != nil {
-		outPayload.SentTime = time.Now()
-		dopts.copts.StatsHandler.HandleRPC(ctx, outPayload)
-	}
-	// t.NewStream(...) could lead to an early rejection of the RPC (e.g., the service/method
-	// does not exist.) so that t.Write could get io.EOF from wait(...). Leave the following
-	// recvResponse to get the final status.
-	if err != nil && err != io.EOF {
-		return err
-	}
-	// Sent successfully.
-	return nil
-}
-
-// Invoke sends the RPC request on the wire and returns after response is received.
-// Invoke is called by generated code. Also users can call Invoke directly when it
-// is really needed in their use cases.
-func Invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) error {
 	if cc.dopts.unaryInt != nil {
 		return cc.dopts.unaryInt(ctx, method, args, reply, cc, invoke, opts...)
 	}
 	return invoke(ctx, method, args, reply, cc, opts...)
 }
 
-func invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) (e error) {
-	c := defaultCallInfo()
-	mc := cc.GetMethodConfig(method)
-	if mc.WaitForReady != nil {
-		c.failFast = !*mc.WaitForReady
-	}
-
-	if mc.Timeout != nil && *mc.Timeout >= 0 {
-		var cancel context.CancelFunc
-		ctx, cancel = context.WithTimeout(ctx, *mc.Timeout)
-		defer cancel()
-	}
+func combine(o1 []CallOption, o2 []CallOption) []CallOption {
+	// we don't use append because o1 could have extra capacity whose
+	// elements would be overwritten, which could cause inadvertent
+	// sharing (and race connditions) between concurrent calls
+	if len(o1) == 0 {
+		return o2
+	} else if len(o2) == 0 {
+		return o1
+	}
+	ret := make([]CallOption, len(o1)+len(o2))
+	copy(ret, o1)
+	copy(ret[len(o1):], o2)
+	return ret
+}
 
-	opts = append(cc.dopts.callOptions, opts...)
-	for _, o := range opts {
-		if err := o.before(c); err != nil {
-			return toRPCErr(err)
-		}
-	}
-	defer func() {
-		for _, o := range opts {
-			o.after(c)
-		}
-	}()
+// Invoke sends the RPC request on the wire and returns after response is
+// received.  This is typically called by generated code.
+//
+// DEPRECATED: Use ClientConn.Invoke instead.
+func Invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) error {
+	return cc.Invoke(ctx, method, args, reply, opts...)
+}
 
-	c.maxSendMessageSize = getMaxSize(mc.MaxReqSize, c.maxSendMessageSize, defaultClientMaxSendMessageSize)
-	c.maxReceiveMessageSize = getMaxSize(mc.MaxRespSize, c.maxReceiveMessageSize, defaultClientMaxReceiveMessageSize)
+var unaryStreamDesc = &StreamDesc{ServerStreams: false, ClientStreams: false}
 
-	if EnableTracing {
-		c.traceInfo.tr = trace.New("grpc.Sent."+methodFamily(method), method)
-		defer c.traceInfo.tr.Finish()
-		c.traceInfo.firstLine.client = true
-		if deadline, ok := ctx.Deadline(); ok {
-			c.traceInfo.firstLine.deadline = deadline.Sub(time.Now())
-		}
-		c.traceInfo.tr.LazyLog(&c.traceInfo.firstLine, false)
-		// TODO(dsymonds): Arrange for c.traceInfo.firstLine.remoteAddr to be set.
-		defer func() {
-			if e != nil {
-				c.traceInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{e}}, true)
-				c.traceInfo.tr.SetError()
-			}
-		}()
-	}
-	ctx = newContextWithRPCInfo(ctx, c.failFast)
-	sh := cc.dopts.copts.StatsHandler
-	if sh != nil {
-		ctx = sh.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method, FailFast: c.failFast})
-		begin := &stats.Begin{
-			Client:    true,
-			BeginTime: time.Now(),
-			FailFast:  c.failFast,
-		}
-		sh.HandleRPC(ctx, begin)
-		defer func() {
-			end := &stats.End{
-				Client:  true,
-				EndTime: time.Now(),
-				Error:   e,
-			}
-			sh.HandleRPC(ctx, end)
-		}()
-	}
-	topts := &transport.Options{
-		Last:  true,
-		Delay: false,
-	}
+func invoke(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, opts ...CallOption) error {
+	// TODO: implement retries in clientStream and make this simply
+	// newClientStream, SendMsg, RecvMsg.
+	firstAttempt := true
 	for {
-		var (
-			err    error
-			t      transport.ClientTransport
-			stream *transport.Stream
-			// Record the done handler from Balancer.Get(...). It is called once the
-			// RPC has completed or failed.
-			done func(balancer.DoneInfo)
-		)
-		// TODO(zhaoq): Need a formal spec of fail-fast.
-		callHdr := &transport.CallHdr{
-			Host:   cc.authority,
-			Method: method,
-		}
-		if cc.dopts.cp != nil {
-			callHdr.SendCompress = cc.dopts.cp.Type()
-		}
-		if c.creds != nil {
-			callHdr.Creds = c.creds
-		}
-
-		t, done, err = cc.getTransport(ctx, c.failFast)
+		csInt, err := newClientStream(ctx, unaryStreamDesc, cc, method, opts...)
 		if err != nil {
-			// TODO(zhaoq): Probably revisit the error handling.
-			if _, ok := status.FromError(err); ok {
-				return err
-			}
-			if err == errConnClosing || err == errConnUnavailable {
-				if c.failFast {
-					return Errorf(codes.Unavailable, "%v", err)
-				}
-				continue
-			}
-			// All the other errors are treated as Internal errors.
-			return Errorf(codes.Internal, "%v", err)
-		}
-		if c.traceInfo.tr != nil {
-			c.traceInfo.tr.LazyLog(&payload{sent: true, msg: args}, true)
-		}
-		stream, err = t.NewStream(ctx, callHdr)
-		if err != nil {
-			if done != nil {
-				if _, ok := err.(transport.ConnectionError); ok {
-					// If error is connection error, transport was sending data on wire,
-					// and we are not sure if anything has been sent on wire.
-					// If error is not connection error, we are sure nothing has been sent.
-					updateRPCInfoInContext(ctx, rpcInfo{bytesSent: true, bytesReceived: false})
-				}
-				done(balancer.DoneInfo{Err: err})
-			}
-			if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
-				continue
-			}
-			return toRPCErr(err)
-		}
-		if peer, ok := peer.FromContext(stream.Context()); ok {
-			c.peer = peer
+			return err
 		}
-		err = sendRequest(ctx, cc.dopts, cc.dopts.cp, c, callHdr, stream, t, args, topts)
-		if err != nil {
-			if done != nil {
-				updateRPCInfoInContext(ctx, rpcInfo{
-					bytesSent:     stream.BytesSent(),
-					bytesReceived: stream.BytesReceived(),
-				})
-				done(balancer.DoneInfo{Err: err})
-			}
-			// Retry a non-failfast RPC when
-			// i) there is a connection error; or
-			// ii) the server started to drain before this RPC was initiated.
-			if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
+		cs := csInt.(*clientStream)
+		if err := cs.SendMsg(req); err != nil {
+			if !cs.c.failFast && cs.attempt.s.Unprocessed() && firstAttempt {
+				// TODO: Add a field to header for grpc-transparent-retry-attempts
+				firstAttempt = false
 				continue
 			}
-			return toRPCErr(err)
+			return err
 		}
-		err = recvResponse(ctx, cc.dopts, t, c, stream, reply)
-		if err != nil {
-			if done != nil {
-				updateRPCInfoInContext(ctx, rpcInfo{
-					bytesSent:     stream.BytesSent(),
-					bytesReceived: stream.BytesReceived(),
-				})
-				done(balancer.DoneInfo{Err: err})
-			}
-			if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
+		if err := cs.RecvMsg(reply); err != nil {
+			if !cs.c.failFast && cs.attempt.s.Unprocessed() && firstAttempt {
+				// TODO: Add a field to header for grpc-transparent-retry-attempts
+				firstAttempt = false
 				continue
 			}
-			return toRPCErr(err)
-		}
-		if c.traceInfo.tr != nil {
-			c.traceInfo.tr.LazyLog(&payload{sent: false, msg: reply}, true)
-		}
-		t.CloseStream(stream, nil)
-		if done != nil {
-			updateRPCInfoInContext(ctx, rpcInfo{
-				bytesSent:     stream.BytesSent(),
-				bytesReceived: stream.BytesReceived(),
-			})
-			done(balancer.DoneInfo{Err: err})
+			return err
 		}
-		return stream.Status().Err()
+		return nil
 	}
 }
diff --git a/vendor/google.golang.org/grpc/clientconn.go b/vendor/google.golang.org/grpc/clientconn.go
index a34bd98..84ba9e5 100644
--- a/vendor/google.golang.org/grpc/clientconn.go
+++ b/vendor/google.golang.org/grpc/clientconn.go
@@ -31,24 +31,54 @@ import (
 	"golang.org/x/net/context"
 	"golang.org/x/net/trace"
 	"google.golang.org/grpc/balancer"
+	_ "google.golang.org/grpc/balancer/roundrobin" // To register roundrobin.
+	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/internal"
+	"google.golang.org/grpc/internal/backoff"
+	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/resolver"
+	_ "google.golang.org/grpc/resolver/dns"         // To register dns resolver.
+	_ "google.golang.org/grpc/resolver/passthrough" // To register passthrough resolver.
 	"google.golang.org/grpc/stats"
+	"google.golang.org/grpc/status"
 	"google.golang.org/grpc/transport"
 )
 
+const (
+	// minimum time to give a connection to complete
+	minConnectTimeout = 20 * time.Second
+	// must match grpclbName in grpclb/grpclb.go
+	grpclbName = "grpclb"
+)
+
 var (
 	// ErrClientConnClosing indicates that the operation is illegal because
 	// the ClientConn is closing.
-	ErrClientConnClosing = errors.New("grpc: the client connection is closing")
-	// ErrClientConnTimeout indicates that the ClientConn cannot establish the
-	// underlying connections within the specified timeout.
-	// DEPRECATED: Please use context.DeadlineExceeded instead.
-	ErrClientConnTimeout = errors.New("grpc: timed out when dialing")
+	//
+	// Deprecated: this error should not be relied upon by users; use the status
+	// code of Canceled instead.
+	ErrClientConnClosing = status.Error(codes.Canceled, "grpc: the client connection is closing")
+	// errConnDrain indicates that the connection starts to be drained and does not accept any new RPCs.
+	errConnDrain = errors.New("grpc: the connection is drained")
+	// errConnClosing indicates that the connection is closing.
+	errConnClosing = errors.New("grpc: the connection is closing")
+	// errConnUnavailable indicates that the connection is unavailable.
+	errConnUnavailable = errors.New("grpc: the connection is unavailable")
+	// errBalancerClosed indicates that the balancer is closed.
+	errBalancerClosed = errors.New("grpc: balancer is closed")
+	// We use an accessor so that minConnectTimeout can be
+	// atomically read and updated while testing.
+	getMinConnectTimeout = func() time.Duration {
+		return minConnectTimeout
+	}
+)
 
+// The following errors are returned from Dial and DialContext
+var (
 	// errNoTransportSecurity indicates that there is no transport security
 	// being set for ClientConn. Users should either set one or explicitly
 	// call WithInsecure DialOption to disable security.
@@ -62,16 +92,6 @@ var (
 	errCredentialsConflict = errors.New("grpc: transport credentials are set for an insecure connection (grpc.WithTransportCredentials() and grpc.WithInsecure() are both called)")
 	// errNetworkIO indicates that the connection is down due to some network I/O error.
 	errNetworkIO = errors.New("grpc: failed with network I/O error")
-	// errConnDrain indicates that the connection starts to be drained and does not accept any new RPCs.
-	errConnDrain = errors.New("grpc: the connection is drained")
-	// errConnClosing indicates that the connection is closing.
-	errConnClosing = errors.New("grpc: the connection is closing")
-	// errConnUnavailable indicates that the connection is unavailable.
-	errConnUnavailable = errors.New("grpc: the connection is unavailable")
-	// errBalancerClosed indicates that the balancer is closed.
-	errBalancerClosed = errors.New("grpc: balancer is closed")
-	// minimum time to give a connection to complete
-	minConnectTimeout = 20 * time.Second
 )
 
 // dialOptions configure a Dial call. dialOptions are set by the DialOption
@@ -79,18 +99,23 @@ var (
 type dialOptions struct {
 	unaryInt    UnaryClientInterceptor
 	streamInt   StreamClientInterceptor
-	codec       Codec
 	cp          Compressor
 	dc          Decompressor
-	bs          backoffStrategy
+	bs          backoff.Strategy
 	block       bool
 	insecure    bool
 	timeout     time.Duration
 	scChan      <-chan ServiceConfig
 	copts       transport.ConnectOptions
 	callOptions []CallOption
-	// This is to support v1 balancer.
+	// This is used by v1 balancer dial option WithBalancer to support v1
+	// balancer, and also by WithBalancerName dial option.
 	balancerBuilder balancer.Builder
+	// This is to support grpclb.
+	resolverBuilder      resolver.Builder
+	waitForHandshake     bool
+	channelzParentID     int64
+	disableServiceConfig bool
 }
 
 const (
@@ -98,9 +123,24 @@ const (
 	defaultClientMaxSendMessageSize    = math.MaxInt32
 )
 
+// RegisterChannelz turns on channelz service.
+// This is an EXPERIMENTAL API.
+func RegisterChannelz() {
+	channelz.TurnOn()
+}
+
 // DialOption configures how we set up the connection.
 type DialOption func(*dialOptions)
 
+// WithWaitForHandshake blocks until the initial settings frame is received from the
+// server before assigning RPCs to the connection.
+// Experimental API.
+func WithWaitForHandshake() DialOption {
+	return func(o *dialOptions) {
+		o.waitForHandshake = true
+	}
+}
+
 // WithWriteBufferSize lets you set the size of write buffer, this determines how much data can be batched
 // before doing a write on the wire.
 func WithWriteBufferSize(s int) DialOption {
@@ -133,7 +173,9 @@ func WithInitialConnWindowSize(s int32) DialOption {
 	}
 }
 
-// WithMaxMsgSize returns a DialOption which sets the maximum message size the client can receive. Deprecated: use WithDefaultCallOptions(MaxCallRecvMsgSize(s)) instead.
+// WithMaxMsgSize returns a DialOption which sets the maximum message size the client can receive.
+//
+// Deprecated: use WithDefaultCallOptions(MaxCallRecvMsgSize(s)) instead.
 func WithMaxMsgSize(s int) DialOption {
 	return WithDefaultCallOptions(MaxCallRecvMsgSize(s))
 }
@@ -146,22 +188,32 @@ func WithDefaultCallOptions(cos ...CallOption) DialOption {
 }
 
 // WithCodec returns a DialOption which sets a codec for message marshaling and unmarshaling.
+//
+// Deprecated: use WithDefaultCallOptions(CallCustomCodec(c)) instead.
 func WithCodec(c Codec) DialOption {
-	return func(o *dialOptions) {
-		o.codec = c
-	}
+	return WithDefaultCallOptions(CallCustomCodec(c))
 }
 
-// WithCompressor returns a DialOption which sets a CompressorGenerator for generating message
-// compressor.
+// WithCompressor returns a DialOption which sets a Compressor to use for
+// message compression. It has lower priority than the compressor set by
+// the UseCompressor CallOption.
+//
+// Deprecated: use UseCompressor instead.
 func WithCompressor(cp Compressor) DialOption {
 	return func(o *dialOptions) {
 		o.cp = cp
 	}
 }
 
-// WithDecompressor returns a DialOption which sets a DecompressorGenerator for generating
-// message decompressor.
+// WithDecompressor returns a DialOption which sets a Decompressor to use for
+// incoming message decompression.  If incoming response messages are encoded
+// using the decompressor's Type(), it will be used.  Otherwise, the message
+// encoding will be used to look up the compressor registered via
+// encoding.RegisterCompressor, which will then be used to decompress the
+// message.  If no compressor is registered for the encoding, an Unimplemented
+// status error will be returned.
+//
+// Deprecated: use encoding.RegisterCompressor instead.
 func WithDecompressor(dc Decompressor) DialOption {
 	return func(o *dialOptions) {
 		o.dc = dc
@@ -170,7 +222,8 @@ func WithDecompressor(dc Decompressor) DialOption {
 
 // WithBalancer returns a DialOption which sets a load balancer with the v1 API.
 // Name resolver will be ignored if this DialOption is specified.
-// Deprecated: use the new balancer APIs in balancer package instead.
+//
+// Deprecated: use the new balancer APIs in balancer package and WithBalancerName.
 func WithBalancer(b Balancer) DialOption {
 	return func(o *dialOptions) {
 		o.balancerBuilder = &balancerWrapperBuilder{
@@ -179,16 +232,35 @@ func WithBalancer(b Balancer) DialOption {
 	}
 }
 
-// WithBalancerBuilder is for testing only. Users using custom balancers should
-// register their balancer and use service config to choose the balancer to use.
-func WithBalancerBuilder(b balancer.Builder) DialOption {
-	// TODO(bar) remove this when switching balancer is done.
+// WithBalancerName sets the balancer that the ClientConn will be initialized
+// with. Balancer registered with balancerName will be used. This function
+// panics if no balancer was registered by balancerName.
+//
+// The balancer cannot be overridden by balancer option specified by service
+// config.
+//
+// This is an EXPERIMENTAL API.
+func WithBalancerName(balancerName string) DialOption {
+	builder := balancer.Get(balancerName)
+	if builder == nil {
+		panic(fmt.Sprintf("grpc.WithBalancerName: no balancer is registered for name %v", balancerName))
+	}
+	return func(o *dialOptions) {
+		o.balancerBuilder = builder
+	}
+}
+
+// withResolverBuilder is only for grpclb.
+func withResolverBuilder(b resolver.Builder) DialOption {
 	return func(o *dialOptions) {
-		o.balancerBuilder = b
+		o.resolverBuilder = b
 	}
 }
 
 // WithServiceConfig returns a DialOption which has a channel to read the service configuration.
+//
+// Deprecated: service config should be received through name resolver, as specified here.
+// https://github.com/grpc/grpc/blob/master/doc/service_config.md
 func WithServiceConfig(c <-chan ServiceConfig) DialOption {
 	return func(o *dialOptions) {
 		o.scChan = c
@@ -207,17 +279,17 @@ func WithBackoffMaxDelay(md time.Duration) DialOption {
 // Use WithBackoffMaxDelay until more parameters on BackoffConfig are opened up
 // for use.
 func WithBackoffConfig(b BackoffConfig) DialOption {
-	// Set defaults to ensure that provided BackoffConfig is valid and
-	// unexported fields get default values.
-	setDefaults(&b)
-	return withBackoff(b)
+
+	return withBackoff(backoff.Exponential{
+		MaxDelay: b.MaxDelay,
+	})
 }
 
-// withBackoff sets the backoff strategy used for retries after a
+// withBackoff sets the backoff strategy used for connectRetryNum after a
 // failed connection attempt.
 //
 // This can be exported if arbitrary backoff strategies are allowed by gRPC.
-func withBackoff(bs backoffStrategy) DialOption {
+func withBackoff(bs backoff.Strategy) DialOption {
 	return func(o *dialOptions) {
 		o.bs = bs
 	}
@@ -258,6 +330,7 @@ func WithPerRPCCredentials(creds credentials.PerRPCCredentials) DialOption {
 
 // WithTimeout returns a DialOption that configures a timeout for dialing a ClientConn
 // initially. This is valid if and only if WithBlock() is present.
+//
 // Deprecated: use DialContext and context.WithTimeout instead.
 func WithTimeout(d time.Duration) DialOption {
 	return func(o *dialOptions) {
@@ -265,18 +338,28 @@ func WithTimeout(d time.Duration) DialOption {
 	}
 }
 
+func withContextDialer(f func(context.Context, string) (net.Conn, error)) DialOption {
+	return func(o *dialOptions) {
+		o.copts.Dialer = f
+	}
+}
+
+func init() {
+	internal.WithContextDialer = withContextDialer
+	internal.WithResolverBuilder = withResolverBuilder
+}
+
 // WithDialer returns a DialOption that specifies a function to use for dialing network addresses.
 // If FailOnNonTempDialError() is set to true, and an error is returned by f, gRPC checks the error's
 // Temporary() method to decide if it should try to reconnect to the network address.
 func WithDialer(f func(string, time.Duration) (net.Conn, error)) DialOption {
-	return func(o *dialOptions) {
-		o.copts.Dialer = func(ctx context.Context, addr string) (net.Conn, error) {
+	return withContextDialer(
+		func(ctx context.Context, addr string) (net.Conn, error) {
 			if deadline, ok := ctx.Deadline(); ok {
 				return f(addr, deadline.Sub(time.Now()))
 			}
 			return f(addr, 0)
-		}
-	}
+		})
 }
 
 // WithStatsHandler returns a DialOption that specifies the stats handler
@@ -335,15 +418,44 @@ func WithAuthority(a string) DialOption {
 	}
 }
 
+// WithChannelzParentID returns a DialOption that specifies the channelz ID of current ClientConn's
+// parent. This function is used in nested channel creation (e.g. grpclb dial).
+func WithChannelzParentID(id int64) DialOption {
+	return func(o *dialOptions) {
+		o.channelzParentID = id
+	}
+}
+
+// WithDisableServiceConfig returns a DialOption that causes grpc to ignore any
+// service config provided by the resolver and provides a hint to the resolver
+// to not fetch service configs.
+func WithDisableServiceConfig() DialOption {
+	return func(o *dialOptions) {
+		o.disableServiceConfig = true
+	}
+}
+
 // Dial creates a client connection to the given target.
 func Dial(target string, opts ...DialOption) (*ClientConn, error) {
 	return DialContext(context.Background(), target, opts...)
 }
 
-// DialContext creates a client connection to the given target. ctx can be used to
-// cancel or expire the pending connection. Once this function returns, the
-// cancellation and expiration of ctx will be noop. Users should call ClientConn.Close
-// to terminate all the pending operations after this function returns.
+// DialContext creates a client connection to the given target. By default, it's
+// a non-blocking dial (the function won't wait for connections to be
+// established, and connecting happens in the background). To make it a blocking
+// dial, use WithBlock() dial option.
+//
+// In the non-blocking case, the ctx does not act against the connection. It
+// only controls the setup steps.
+//
+// In the blocking case, ctx can be used to cancel or expire the pending
+// connection. Once this function returns, the cancellation and expiration of
+// ctx will be noop. Users should call ClientConn.Close to terminate all the
+// pending operations after this function returns.
+//
+// The target name syntax is defined in
+// https://github.com/grpc/grpc/blob/master/doc/naming.md.
+// e.g. to use dns resolver, a "dns:///" prefix should be applied to the target.
 func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *ClientConn, err error) {
 	cc := &ClientConn{
 		target: target,
@@ -358,6 +470,14 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		opt(&cc.dopts)
 	}
 
+	if channelz.IsOn() {
+		if cc.dopts.channelzParentID != 0 {
+			cc.channelzID = channelz.RegisterChannel(cc, cc.dopts.channelzParentID, target)
+		} else {
+			cc.channelzID = channelz.RegisterChannel(cc, 0, target)
+		}
+	}
+
 	if !cc.dopts.insecure {
 		if cc.dopts.copts.TransportCredentials == nil {
 			return nil, errNoTransportSecurity
@@ -378,7 +498,8 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 	if cc.dopts.copts.Dialer == nil {
 		cc.dopts.copts.Dialer = newProxyDialer(
 			func(ctx context.Context, addr string) (net.Conn, error) {
-				return (&net.Dialer{}).DialContext(ctx, "tcp", addr)
+				network, addr := parseDialTarget(addr)
+				return dialContext(ctx, network, addr)
 			},
 		)
 	}
@@ -419,12 +540,29 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		default:
 		}
 	}
-	// Set defaults.
-	if cc.dopts.codec == nil {
-		cc.dopts.codec = protoCodec{}
-	}
 	if cc.dopts.bs == nil {
-		cc.dopts.bs = DefaultBackoffConfig
+		cc.dopts.bs = backoff.Exponential{
+			MaxDelay: DefaultBackoffConfig.MaxDelay,
+		}
+	}
+	if cc.dopts.resolverBuilder == nil {
+		// Only try to parse target when resolver builder is not already set.
+		cc.parsedTarget = parseTarget(cc.target)
+		grpclog.Infof("parsed scheme: %q", cc.parsedTarget.Scheme)
+		cc.dopts.resolverBuilder = resolver.Get(cc.parsedTarget.Scheme)
+		if cc.dopts.resolverBuilder == nil {
+			// If resolver builder is still nil, the parse target's scheme is
+			// not registered. Fallback to default resolver and set Endpoint to
+			// the original unparsed target.
+			grpclog.Infof("scheme %q not registered, fallback to default scheme", cc.parsedTarget.Scheme)
+			cc.parsedTarget = resolver.Target{
+				Scheme:   resolver.GetDefaultScheme(),
+				Endpoint: target,
+			}
+			cc.dopts.resolverBuilder = resolver.Get(cc.parsedTarget.Scheme)
+		}
+	} else {
+		cc.parsedTarget = resolver.Target{Endpoint: target}
 	}
 	creds := cc.dopts.copts.TransportCredentials
 	if creds != nil && creds.Info().ServerName != "" {
@@ -432,45 +570,11 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 	} else if cc.dopts.insecure && cc.dopts.copts.Authority != "" {
 		cc.authority = cc.dopts.copts.Authority
 	} else {
-		cc.authority = target
+		// Use endpoint from "scheme://authority/endpoint" as the default
+		// authority for ClientConn.
+		cc.authority = cc.parsedTarget.Endpoint
 	}
 
-	if cc.dopts.balancerBuilder != nil {
-		var credsClone credentials.TransportCredentials
-		if creds != nil {
-			credsClone = creds.Clone()
-		}
-		buildOpts := balancer.BuildOptions{
-			DialCreds: credsClone,
-			Dialer:    cc.dopts.copts.Dialer,
-		}
-		// Build should not take long time. So it's ok to not have a goroutine for it.
-		// TODO(bar) init balancer after first resolver result to support service config balancer.
-		cc.balancerWrapper = newCCBalancerWrapper(cc, cc.dopts.balancerBuilder, buildOpts)
-	} else {
-		waitC := make(chan error, 1)
-		go func() {
-			defer close(waitC)
-			// No balancer, or no resolver within the balancer.  Connect directly.
-			ac, err := cc.newAddrConn([]resolver.Address{{Addr: target}})
-			if err != nil {
-				waitC <- err
-				return
-			}
-			if err := ac.connect(cc.dopts.block); err != nil {
-				waitC <- err
-				return
-			}
-		}()
-		select {
-		case <-ctx.Done():
-			return nil, ctx.Err()
-		case err := <-waitC:
-			if err != nil {
-				return nil, err
-			}
-		}
-	}
 	if cc.dopts.scChan != nil && !scSet {
 		// Blocking wait for the initial service config.
 		select {
@@ -486,19 +590,29 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		go cc.scWatcher()
 	}
 
+	var credsClone credentials.TransportCredentials
+	if creds := cc.dopts.copts.TransportCredentials; creds != nil {
+		credsClone = creds.Clone()
+	}
+	cc.balancerBuildOpts = balancer.BuildOptions{
+		DialCreds:        credsClone,
+		Dialer:           cc.dopts.copts.Dialer,
+		ChannelzParentID: cc.channelzID,
+	}
+
 	// Build the resolver.
 	cc.resolverWrapper, err = newCCResolverWrapper(cc)
 	if err != nil {
 		return nil, fmt.Errorf("failed to build resolver: %v", err)
 	}
-
-	if cc.balancerWrapper != nil && cc.resolverWrapper == nil {
-		// TODO(bar) there should always be a resolver (DNS as the default).
-		// Unblock balancer initialization with a fake resolver update if there's no resolver.
-		// The balancer wrapper will not read the addresses, so an empty list works.
-		// TODO(bar) remove this after the real resolver is started.
-		cc.balancerWrapper.handleResolvedAddrs([]resolver.Address{}, nil)
-	}
+	// Start the resolver wrapper goroutine after resolverWrapper is created.
+	//
+	// If the goroutine is started before resolverWrapper is ready, the
+	// following may happen: The goroutine sends updates to cc. cc forwards
+	// those to balancer. Balancer creates new addrConn. addrConn fails to
+	// connect, and calls resolveNow(). resolveNow() tries to use the non-ready
+	// resolverWrapper.
+	cc.resolverWrapper.start()
 
 	// A blocking dial blocks until the clientConn is ready.
 	if cc.dopts.block {
@@ -565,21 +679,33 @@ type ClientConn struct {
 	ctx    context.Context
 	cancel context.CancelFunc
 
-	target    string
-	authority string
-	dopts     dialOptions
-	csMgr     *connectivityStateManager
-
-	balancerWrapper *ccBalancerWrapper
-	resolverWrapper *ccResolverWrapper
+	target       string
+	parsedTarget resolver.Target
+	authority    string
+	dopts        dialOptions
+	csMgr        *connectivityStateManager
 
-	blockingpicker *pickerWrapper
+	balancerBuildOpts balancer.BuildOptions
+	resolverWrapper   *ccResolverWrapper
+	blockingpicker    *pickerWrapper
 
 	mu    sync.RWMutex
 	sc    ServiceConfig
+	scRaw string
 	conns map[*addrConn]struct{}
 	// Keepalive parameter can be updated if a GoAway is received.
-	mkp keepalive.ClientParameters
+	mkp             keepalive.ClientParameters
+	curBalancerName string
+	preBalancerName string // previous balancer name.
+	curAddresses    []resolver.Address
+	balancerWrapper *ccBalancerWrapper
+
+	channelzID          int64 // channelz unique identification number
+	czmu                sync.RWMutex
+	callsStarted        int64
+	callsSucceeded      int64
+	callsFailed         int64
+	lastCallStartedTime time.Time
 }
 
 // WaitForStateChange waits until the connectivity.State of ClientConn changes from sourceState or
@@ -615,6 +741,7 @@ func (cc *ClientConn) scWatcher() {
 			// TODO: load balance policy runtime change is ignored.
 			// We may revist this decision in the future.
 			cc.sc = sc
+			cc.scRaw = ""
 			cc.mu.Unlock()
 		case <-cc.ctx.Done():
 			return
@@ -622,7 +749,115 @@ func (cc *ClientConn) scWatcher() {
 	}
 }
 
+func (cc *ClientConn) handleResolvedAddrs(addrs []resolver.Address, err error) {
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+	if cc.conns == nil {
+		// cc was closed.
+		return
+	}
+
+	if reflect.DeepEqual(cc.curAddresses, addrs) {
+		return
+	}
+
+	cc.curAddresses = addrs
+
+	if cc.dopts.balancerBuilder == nil {
+		// Only look at balancer types and switch balancer if balancer dial
+		// option is not set.
+		var isGRPCLB bool
+		for _, a := range addrs {
+			if a.Type == resolver.GRPCLB {
+				isGRPCLB = true
+				break
+			}
+		}
+		var newBalancerName string
+		if isGRPCLB {
+			newBalancerName = grpclbName
+		} else {
+			// Address list doesn't contain grpclb address. Try to pick a
+			// non-grpclb balancer.
+			newBalancerName = cc.curBalancerName
+			// If current balancer is grpclb, switch to the previous one.
+			if newBalancerName == grpclbName {
+				newBalancerName = cc.preBalancerName
+			}
+			// The following could be true in two cases:
+			// - the first time handling resolved addresses
+			//   (curBalancerName="")
+			// - the first time handling non-grpclb addresses
+			//   (curBalancerName="grpclb", preBalancerName="")
+			if newBalancerName == "" {
+				newBalancerName = PickFirstBalancerName
+			}
+		}
+		cc.switchBalancer(newBalancerName)
+	} else if cc.balancerWrapper == nil {
+		// Balancer dial option was set, and this is the first time handling
+		// resolved addresses. Build a balancer with dopts.balancerBuilder.
+		cc.balancerWrapper = newCCBalancerWrapper(cc, cc.dopts.balancerBuilder, cc.balancerBuildOpts)
+	}
+
+	cc.balancerWrapper.handleResolvedAddrs(addrs, nil)
+}
+
+// switchBalancer starts the switching from current balancer to the balancer
+// with the given name.
+//
+// It will NOT send the current address list to the new balancer. If needed,
+// caller of this function should send address list to the new balancer after
+// this function returns.
+//
+// Caller must hold cc.mu.
+func (cc *ClientConn) switchBalancer(name string) {
+	if cc.conns == nil {
+		return
+	}
+
+	if strings.ToLower(cc.curBalancerName) == strings.ToLower(name) {
+		return
+	}
+
+	grpclog.Infof("ClientConn switching balancer to %q", name)
+	if cc.dopts.balancerBuilder != nil {
+		grpclog.Infoln("ignoring balancer switching: Balancer DialOption used instead")
+		return
+	}
+	// TODO(bar switching) change this to two steps: drain and close.
+	// Keep track of sc in wrapper.
+	if cc.balancerWrapper != nil {
+		cc.balancerWrapper.close()
+	}
+	// Clear all stickiness state.
+	cc.blockingpicker.clearStickinessState()
+
+	builder := balancer.Get(name)
+	if builder == nil {
+		grpclog.Infof("failed to get balancer builder for: %v, using pick_first instead", name)
+		builder = newPickfirstBuilder()
+	}
+	cc.preBalancerName = cc.curBalancerName
+	cc.curBalancerName = builder.Name()
+	cc.balancerWrapper = newCCBalancerWrapper(cc, builder, cc.balancerBuildOpts)
+}
+
+func (cc *ClientConn) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
+	cc.mu.Lock()
+	if cc.conns == nil {
+		cc.mu.Unlock()
+		return
+	}
+	// TODO(bar switching) send updates to all balancer wrappers when balancer
+	// gracefully switching is supported.
+	cc.balancerWrapper.handleSubConnStateChange(sc, s)
+	cc.mu.Unlock()
+}
+
 // newAddrConn creates an addrConn for addrs and adds it to cc.conns.
+//
+// Caller needs to make sure len(addrs) > 0.
 func (cc *ClientConn) newAddrConn(addrs []resolver.Address) (*addrConn, error) {
 	ac := &addrConn{
 		cc:    cc,
@@ -636,6 +871,9 @@ func (cc *ClientConn) newAddrConn(addrs []resolver.Address) (*addrConn, error) {
 		cc.mu.Unlock()
 		return nil, ErrClientConnClosing
 	}
+	if channelz.IsOn() {
+		ac.channelzID = channelz.RegisterSubChannel(ac, cc.channelzID, "")
+	}
 	cc.conns[ac] = struct{}{}
 	cc.mu.Unlock()
 	return ac, nil
@@ -654,12 +892,48 @@ func (cc *ClientConn) removeAddrConn(ac *addrConn, err error) {
 	ac.tearDown(err)
 }
 
+// ChannelzMetric returns ChannelInternalMetric of current ClientConn.
+// This is an EXPERIMENTAL API.
+func (cc *ClientConn) ChannelzMetric() *channelz.ChannelInternalMetric {
+	state := cc.GetState()
+	cc.czmu.RLock()
+	defer cc.czmu.RUnlock()
+	return &channelz.ChannelInternalMetric{
+		State:                    state,
+		Target:                   cc.target,
+		CallsStarted:             cc.callsStarted,
+		CallsSucceeded:           cc.callsSucceeded,
+		CallsFailed:              cc.callsFailed,
+		LastCallStartedTimestamp: cc.lastCallStartedTime,
+	}
+}
+
+func (cc *ClientConn) incrCallsStarted() {
+	cc.czmu.Lock()
+	cc.callsStarted++
+	// TODO(yuxuanli): will make this a time.Time pointer improve performance?
+	cc.lastCallStartedTime = time.Now()
+	cc.czmu.Unlock()
+}
+
+func (cc *ClientConn) incrCallsSucceeded() {
+	cc.czmu.Lock()
+	cc.callsSucceeded++
+	cc.czmu.Unlock()
+}
+
+func (cc *ClientConn) incrCallsFailed() {
+	cc.czmu.Lock()
+	cc.callsFailed++
+	cc.czmu.Unlock()
+}
+
 // connect starts to creating transport and also starts the transport monitor
 // goroutine for this ac.
 // It does nothing if the ac is not IDLE.
 // TODO(bar) Move this to the addrConn section.
 // This was part of resetAddrConn, keep it here to make the diff look clean.
-func (ac *addrConn) connect(block bool) error {
+func (ac *addrConn) connect() error {
 	ac.mu.Lock()
 	if ac.state == connectivity.Shutdown {
 		ac.mu.Unlock()
@@ -670,39 +944,21 @@ func (ac *addrConn) connect(block bool) error {
 		return nil
 	}
 	ac.state = connectivity.Connecting
-	if ac.cc.balancerWrapper != nil {
-		ac.cc.balancerWrapper.handleSubConnStateChange(ac.acbw, ac.state)
-	} else {
-		ac.cc.csMgr.updateState(ac.state)
-	}
+	ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
 	ac.mu.Unlock()
 
-	if block {
+	// Start a goroutine connecting to the server asynchronously.
+	go func() {
 		if err := ac.resetTransport(); err != nil {
+			grpclog.Warningf("Failed to dial %s: %v; please retry.", ac.addrs[0].Addr, err)
 			if err != errConnClosing {
+				// Keep this ac in cc.conns, to get the reason it's torn down.
 				ac.tearDown(err)
 			}
-			if e, ok := err.(transport.ConnectionError); ok && !e.Temporary() {
-				return e.Origin()
-			}
-			return err
+			return
 		}
-		// Start to monitor the error status of transport.
-		go ac.transportMonitor()
-	} else {
-		// Start a goroutine connecting to the server asynchronously.
-		go func() {
-			if err := ac.resetTransport(); err != nil {
-				grpclog.Warningf("Failed to dial %s: %v; please retry.", ac.addrs[0].Addr, err)
-				if err != errConnClosing {
-					// Keep this ac in cc.conns, to get the reason it's torn down.
-					ac.tearDown(err)
-				}
-				return
-			}
-			ac.transportMonitor()
-		}()
-	}
+		ac.transportMonitor()
+	}()
 	return nil
 }
 
@@ -731,6 +987,7 @@ func (ac *addrConn) tryUpdateAddrs(addrs []resolver.Address) bool {
 	grpclog.Infof("addrConn: tryUpdateAddrs curAddrFound: %v", curAddrFound)
 	if curAddrFound {
 		ac.addrs = addrs
+		ac.reconnectIdx = 0 // Start reconnecting from beginning in the new list.
 	}
 
 	return curAddrFound
@@ -741,7 +998,7 @@ func (ac *addrConn) tryUpdateAddrs(addrs []resolver.Address) bool {
 // the corresponding MethodConfig.
 // If there isn't an exact match for the input method, we look for the default config
 // under the service (i.e /service/). If there is a default MethodConfig for
-// the serivce, we return it.
+// the service, we return it.
 // Otherwise, we return an empty MethodConfig.
 func (cc *ClientConn) GetMethodConfig(method string) MethodConfig {
 	// TODO: Avoid the locking here.
@@ -750,37 +1007,12 @@ func (cc *ClientConn) GetMethodConfig(method string) MethodConfig {
 	m, ok := cc.sc.Methods[method]
 	if !ok {
 		i := strings.LastIndex(method, "/")
-		m, _ = cc.sc.Methods[method[:i+1]]
+		m = cc.sc.Methods[method[:i+1]]
 	}
 	return m
 }
 
 func (cc *ClientConn) getTransport(ctx context.Context, failfast bool) (transport.ClientTransport, func(balancer.DoneInfo), error) {
-	if cc.balancerWrapper == nil {
-		// If balancer is nil, there should be only one addrConn available.
-		cc.mu.RLock()
-		if cc.conns == nil {
-			cc.mu.RUnlock()
-			// TODO this function returns toRPCErr and non-toRPCErr. Clean up
-			// the errors in ClientConn.
-			return nil, nil, toRPCErr(ErrClientConnClosing)
-		}
-		var ac *addrConn
-		for ac = range cc.conns {
-			// Break after the first iteration to get the first addrConn.
-			break
-		}
-		cc.mu.RUnlock()
-		if ac == nil {
-			return nil, nil, errConnClosing
-		}
-		t, err := ac.wait(ctx, false /*hasBalancer*/, failfast)
-		if err != nil {
-			return nil, nil, err
-		}
-		return t, nil, nil
-	}
-
 	t, done, err := cc.blockingpicker.pick(ctx, failfast, balancer.PickOptions{})
 	if err != nil {
 		return nil, nil, toRPCErr(err)
@@ -788,9 +1020,61 @@ func (cc *ClientConn) getTransport(ctx context.Context, failfast bool) (transpor
 	return t, done, nil
 }
 
+// handleServiceConfig parses the service config string in JSON format to Go native
+// struct ServiceConfig, and store both the struct and the JSON string in ClientConn.
+func (cc *ClientConn) handleServiceConfig(js string) error {
+	if cc.dopts.disableServiceConfig {
+		return nil
+	}
+	sc, err := parseServiceConfig(js)
+	if err != nil {
+		return err
+	}
+	cc.mu.Lock()
+	cc.scRaw = js
+	cc.sc = sc
+	if sc.LB != nil && *sc.LB != grpclbName { // "grpclb" is not a valid balancer option in service config.
+		if cc.curBalancerName == grpclbName {
+			// If current balancer is grpclb, there's at least one grpclb
+			// balancer address in the resolved list. Don't switch the balancer,
+			// but change the previous balancer name, so if a new resolved
+			// address list doesn't contain grpclb address, balancer will be
+			// switched to *sc.LB.
+			cc.preBalancerName = *sc.LB
+		} else {
+			cc.switchBalancer(*sc.LB)
+			cc.balancerWrapper.handleResolvedAddrs(cc.curAddresses, nil)
+		}
+	}
+
+	if envConfigStickinessOn {
+		var newStickinessMDKey string
+		if sc.stickinessMetadataKey != nil && *sc.stickinessMetadataKey != "" {
+			newStickinessMDKey = *sc.stickinessMetadataKey
+		}
+		// newStickinessMDKey is "" if one of the following happens:
+		// - stickinessMetadataKey is set to ""
+		// - stickinessMetadataKey field doesn't exist in service config
+		cc.blockingpicker.updateStickinessMDKey(strings.ToLower(newStickinessMDKey))
+	}
+
+	cc.mu.Unlock()
+	return nil
+}
+
+func (cc *ClientConn) resolveNow(o resolver.ResolveNowOption) {
+	cc.mu.RLock()
+	r := cc.resolverWrapper
+	cc.mu.RUnlock()
+	if r == nil {
+		return
+	}
+	go r.resolveNow(o)
+}
+
 // Close tears down the ClientConn and all underlying connections.
 func (cc *ClientConn) Close() error {
-	cc.cancel()
+	defer cc.cancel()
 
 	cc.mu.Lock()
 	if cc.conns == nil {
@@ -800,17 +1084,28 @@ func (cc *ClientConn) Close() error {
 	conns := cc.conns
 	cc.conns = nil
 	cc.csMgr.updateState(connectivity.Shutdown)
+
+	rWrapper := cc.resolverWrapper
+	cc.resolverWrapper = nil
+	bWrapper := cc.balancerWrapper
+	cc.balancerWrapper = nil
 	cc.mu.Unlock()
+
 	cc.blockingpicker.close()
-	if cc.resolverWrapper != nil {
-		cc.resolverWrapper.close()
+
+	if rWrapper != nil {
+		rWrapper.close()
 	}
-	if cc.balancerWrapper != nil {
-		cc.balancerWrapper.close()
+	if bWrapper != nil {
+		bWrapper.close()
 	}
+
 	for ac := range conns {
 		ac.tearDown(ErrClientConnClosing)
 	}
+	if channelz.IsOn() {
+		channelz.RemoveEntry(cc.channelzID)
+	}
 	return nil
 }
 
@@ -819,15 +1114,16 @@ type addrConn struct {
 	ctx    context.Context
 	cancel context.CancelFunc
 
-	cc      *ClientConn
-	curAddr resolver.Address
-	addrs   []resolver.Address
-	dopts   dialOptions
-	events  trace.EventLog
-	acbw    balancer.SubConn
+	cc     *ClientConn
+	addrs  []resolver.Address
+	dopts  dialOptions
+	events trace.EventLog
+	acbw   balancer.SubConn
 
-	mu    sync.Mutex
-	state connectivity.State
+	mu           sync.Mutex
+	curAddr      resolver.Address
+	reconnectIdx int // The index in addrs list to start reconnecting from.
+	state        connectivity.State
 	// ready is closed and becomes nil when a new transport is up or failed
 	// due to timeout.
 	ready     chan struct{}
@@ -835,13 +1131,28 @@ type addrConn struct {
 
 	// The reason this addrConn is torn down.
 	tearDownErr error
+
+	connectRetryNum int
+	// backoffDeadline is the time until which resetTransport needs to
+	// wait before increasing connectRetryNum count.
+	backoffDeadline time.Time
+	// connectDeadline is the time by which all connection
+	// negotiations must complete.
+	connectDeadline time.Time
+
+	channelzID          int64 // channelz unique identification number
+	czmu                sync.RWMutex
+	callsStarted        int64
+	callsSucceeded      int64
+	callsFailed         int64
+	lastCallStartedTime time.Time
 }
 
 // adjustParams updates parameters used to create transports upon
 // receiving a GoAway.
 func (ac *addrConn) adjustParams(r transport.GoAwayReason) {
 	switch r {
-	case transport.TooManyPings:
+	case transport.GoAwayTooManyPings:
 		v := 2 * ac.dopts.copts.KeepaliveParams.Time
 		ac.cc.mu.Lock()
 		if v > ac.cc.mkp.Time {
@@ -869,6 +1180,16 @@ func (ac *addrConn) errorf(format string, a ...interface{}) {
 
 // resetTransport recreates a transport to the address for ac.  The old
 // transport will close itself on error or when the clientconn is closed.
+// The created transport must receive initial settings frame from the server.
+// In case that doesn't happen, transportMonitor will kill the newly created
+// transport after connectDeadline has expired.
+// In case there was an error on the transport before the settings frame was
+// received, resetTransport resumes connecting to backends after the one that
+// was previously connected to. In case end of the list is reached, resetTransport
+// backs off until the original deadline.
+// If the DialOption WithWaitForHandshake was set, resetTrasport returns
+// successfully only after server settings are received.
+//
 // TODO(bar) make sure all state transitions are valid.
 func (ac *addrConn) resetTransport() error {
 	ac.mu.Lock()
@@ -876,135 +1197,222 @@ func (ac *addrConn) resetTransport() error {
 		ac.mu.Unlock()
 		return errConnClosing
 	}
-	ac.state = connectivity.TransientFailure
-	if ac.cc.balancerWrapper != nil {
-		ac.cc.balancerWrapper.handleSubConnStateChange(ac.acbw, ac.state)
-	} else {
-		ac.cc.csMgr.updateState(ac.state)
-	}
 	if ac.ready != nil {
 		close(ac.ready)
 		ac.ready = nil
 	}
 	ac.transport = nil
-	ac.curAddr = resolver.Address{}
+	ridx := ac.reconnectIdx
 	ac.mu.Unlock()
 	ac.cc.mu.RLock()
 	ac.dopts.copts.KeepaliveParams = ac.cc.mkp
 	ac.cc.mu.RUnlock()
-	for retries := 0; ; retries++ {
-		sleepTime := ac.dopts.bs.backoff(retries)
-		timeout := minConnectTimeout
+	var backoffDeadline, connectDeadline time.Time
+	for connectRetryNum := 0; ; connectRetryNum++ {
 		ac.mu.Lock()
-		if timeout < time.Duration(int(sleepTime)/len(ac.addrs)) {
-			timeout = time.Duration(int(sleepTime) / len(ac.addrs))
+		if ac.backoffDeadline.IsZero() {
+			// This means either a successful HTTP2 connection was established
+			// or this is the first time this addrConn is trying to establish a
+			// connection.
+			backoffFor := ac.dopts.bs.Backoff(connectRetryNum) // time.Duration.
+			// This will be the duration that dial gets to finish.
+			dialDuration := getMinConnectTimeout()
+			if backoffFor > dialDuration {
+				// Give dial more time as we keep failing to connect.
+				dialDuration = backoffFor
+			}
+			start := time.Now()
+			backoffDeadline = start.Add(backoffFor)
+			connectDeadline = start.Add(dialDuration)
+			ridx = 0 // Start connecting from the beginning.
+		} else {
+			// Continue trying to connect with the same deadlines.
+			connectRetryNum = ac.connectRetryNum
+			backoffDeadline = ac.backoffDeadline
+			connectDeadline = ac.connectDeadline
+			ac.backoffDeadline = time.Time{}
+			ac.connectDeadline = time.Time{}
+			ac.connectRetryNum = 0
 		}
-		connectTime := time.Now()
 		if ac.state == connectivity.Shutdown {
 			ac.mu.Unlock()
 			return errConnClosing
 		}
 		ac.printf("connecting")
-		ac.state = connectivity.Connecting
-		// TODO(bar) remove condition once we always have a balancer.
-		if ac.cc.balancerWrapper != nil {
-			ac.cc.balancerWrapper.handleSubConnStateChange(ac.acbw, ac.state)
-		} else {
-			ac.cc.csMgr.updateState(ac.state)
+		if ac.state != connectivity.Connecting {
+			ac.state = connectivity.Connecting
+			ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
 		}
 		// copy ac.addrs in case of race
 		addrsIter := make([]resolver.Address, len(ac.addrs))
 		copy(addrsIter, ac.addrs)
 		copts := ac.dopts.copts
 		ac.mu.Unlock()
-		for _, addr := range addrsIter {
+		connected, err := ac.createTransport(connectRetryNum, ridx, backoffDeadline, connectDeadline, addrsIter, copts)
+		if err != nil {
+			return err
+		}
+		if connected {
+			return nil
+		}
+	}
+}
+
+// createTransport creates a connection to one of the backends in addrs.
+// It returns true if a connection was established.
+func (ac *addrConn) createTransport(connectRetryNum, ridx int, backoffDeadline, connectDeadline time.Time, addrs []resolver.Address, copts transport.ConnectOptions) (bool, error) {
+	for i := ridx; i < len(addrs); i++ {
+		addr := addrs[i]
+		target := transport.TargetInfo{
+			Addr:      addr.Addr,
+			Metadata:  addr.Metadata,
+			Authority: ac.cc.authority,
+		}
+		done := make(chan struct{})
+		onPrefaceReceipt := func() {
 			ac.mu.Lock()
-			if ac.state == connectivity.Shutdown {
-				// ac.tearDown(...) has been invoked.
-				ac.mu.Unlock()
-				return errConnClosing
+			close(done)
+			if !ac.backoffDeadline.IsZero() {
+				// If we haven't already started reconnecting to
+				// other backends.
+				// Note, this can happen when writer notices an error
+				// and triggers resetTransport while at the same time
+				// reader receives the preface and invokes this closure.
+				ac.backoffDeadline = time.Time{}
+				ac.connectDeadline = time.Time{}
+				ac.connectRetryNum = 0
 			}
 			ac.mu.Unlock()
-			sinfo := transport.TargetInfo{
-				Addr:     addr.Addr,
-				Metadata: addr.Metadata,
-			}
-			newTransport, err := transport.NewClientTransport(ac.cc.ctx, sinfo, copts, timeout)
-			if err != nil {
-				if e, ok := err.(transport.ConnectionError); ok && !e.Temporary() {
-					return err
-				}
-				grpclog.Warningf("grpc: addrConn.resetTransport failed to create client transport: %v; Reconnecting to %v", err, addr)
-				ac.mu.Lock()
-				if ac.state == connectivity.Shutdown {
-					// ac.tearDown(...) has been invoked.
-					ac.mu.Unlock()
-					return errConnClosing
-				}
-				ac.mu.Unlock()
-				continue
-			}
+		}
+		// Do not cancel in the success path because of
+		// this issue in Go1.6: https://github.com/golang/go/issues/15078.
+		connectCtx, cancel := context.WithDeadline(ac.ctx, connectDeadline)
+		if channelz.IsOn() {
+			copts.ChannelzParentID = ac.channelzID
+		}
+		newTr, err := transport.NewClientTransport(connectCtx, ac.cc.ctx, target, copts, onPrefaceReceipt)
+		if err != nil {
+			cancel()
+			ac.cc.blockingpicker.updateConnectionError(err)
 			ac.mu.Lock()
-			ac.printf("ready")
 			if ac.state == connectivity.Shutdown {
 				// ac.tearDown(...) has been invoked.
 				ac.mu.Unlock()
-				newTransport.Close()
-				return errConnClosing
-			}
-			ac.state = connectivity.Ready
-			if ac.cc.balancerWrapper != nil {
-				ac.cc.balancerWrapper.handleSubConnStateChange(ac.acbw, ac.state)
-			} else {
-				ac.cc.csMgr.updateState(ac.state)
-			}
-			t := ac.transport
-			ac.transport = newTransport
-			if t != nil {
-				t.Close()
-			}
-			ac.curAddr = addr
-			if ac.ready != nil {
-				close(ac.ready)
-				ac.ready = nil
+				return false, errConnClosing
 			}
 			ac.mu.Unlock()
-			return nil
+			grpclog.Warningf("grpc: addrConn.createTransport failed to connect to %v. Err :%v. Reconnecting...", addr, err)
+			continue
+		}
+		if ac.dopts.waitForHandshake {
+			select {
+			case <-done:
+			case <-connectCtx.Done():
+				// Didn't receive server preface, must kill this new transport now.
+				grpclog.Warningf("grpc: addrConn.createTransport failed to receive server preface before deadline.")
+				newTr.Close()
+				break
+			case <-ac.ctx.Done():
+			}
 		}
 		ac.mu.Lock()
-		ac.state = connectivity.TransientFailure
-		if ac.cc.balancerWrapper != nil {
-			ac.cc.balancerWrapper.handleSubConnStateChange(ac.acbw, ac.state)
-		} else {
-			ac.cc.csMgr.updateState(ac.state)
+		if ac.state == connectivity.Shutdown {
+			ac.mu.Unlock()
+			// ac.tearDonn(...) has been invoked.
+			newTr.Close()
+			return false, errConnClosing
 		}
+		ac.printf("ready")
+		ac.state = connectivity.Ready
+		ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
+		ac.transport = newTr
+		ac.curAddr = addr
 		if ac.ready != nil {
 			close(ac.ready)
 			ac.ready = nil
 		}
-		ac.mu.Unlock()
-		timer := time.NewTimer(sleepTime - time.Since(connectTime))
 		select {
-		case <-timer.C:
-		case <-ac.ctx.Done():
-			timer.Stop()
-			return ac.ctx.Err()
+		case <-done:
+			// If the server has responded back with preface already,
+			// don't set the reconnect parameters.
+		default:
+			ac.connectRetryNum = connectRetryNum
+			ac.backoffDeadline = backoffDeadline
+			ac.connectDeadline = connectDeadline
+			ac.reconnectIdx = i + 1 // Start reconnecting from the next backend in the list.
 		}
+		ac.mu.Unlock()
+		return true, nil
+	}
+	ac.mu.Lock()
+	if ac.state == connectivity.Shutdown {
+		ac.mu.Unlock()
+		return false, errConnClosing
+	}
+	ac.state = connectivity.TransientFailure
+	ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
+	ac.cc.resolveNow(resolver.ResolveNowOption{})
+	if ac.ready != nil {
+		close(ac.ready)
+		ac.ready = nil
+	}
+	ac.mu.Unlock()
+	timer := time.NewTimer(backoffDeadline.Sub(time.Now()))
+	select {
+	case <-timer.C:
+	case <-ac.ctx.Done():
 		timer.Stop()
+		return false, ac.ctx.Err()
 	}
+	return false, nil
 }
 
 // Run in a goroutine to track the error in transport and create the
 // new transport if an error happens. It returns when the channel is closing.
 func (ac *addrConn) transportMonitor() {
 	for {
+		var timer *time.Timer
+		var cdeadline <-chan time.Time
 		ac.mu.Lock()
 		t := ac.transport
+		if !ac.connectDeadline.IsZero() {
+			timer = time.NewTimer(ac.connectDeadline.Sub(time.Now()))
+			cdeadline = timer.C
+		}
 		ac.mu.Unlock()
 		// Block until we receive a goaway or an error occurs.
 		select {
 		case <-t.GoAway():
+			done := t.Error()
+			cleanup := t.Close
+			// Since this transport will be orphaned (won't have a transportMonitor)
+			// we need to launch a goroutine to keep track of clientConn.Close()
+			// happening since it might not be noticed by any other goroutine for a while.
+			go func() {
+				<-done
+				cleanup()
+			}()
 		case <-t.Error():
+			// In case this is triggered because clientConn.Close()
+			// was called, we want to immeditately close the transport
+			// since no other goroutine might notice it for a while.
+			t.Close()
+		case <-cdeadline:
+			ac.mu.Lock()
+			// This implies that client received server preface.
+			if ac.backoffDeadline.IsZero() {
+				ac.mu.Unlock()
+				continue
+			}
+			ac.mu.Unlock()
+			timer = nil
+			// No server preface received until deadline.
+			// Kill the connection.
+			grpclog.Warningf("grpc: addrConn.transportMonitor didn't get server preface after waiting. Closing the new transport now.")
+			t.Close()
+		}
+		if timer != nil {
+			timer.Stop()
 		}
 		// If a GoAway happened, regardless of error, adjust our keepalive
 		// parameters as appropriate.
@@ -1013,6 +1421,18 @@ func (ac *addrConn) transportMonitor() {
 			ac.adjustParams(t.GetGoAwayReason())
 		default:
 		}
+		ac.mu.Lock()
+		if ac.state == connectivity.Shutdown {
+			ac.mu.Unlock()
+			return
+		}
+		// Set connectivity state to TransientFailure before calling
+		// resetTransport. Transition READY->CONNECTING is not valid.
+		ac.state = connectivity.TransientFailure
+		ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
+		ac.cc.resolveNow(resolver.ResolveNowOption{})
+		ac.curAddr = resolver.Address{}
+		ac.mu.Unlock()
 		if err := ac.resetTransport(); err != nil {
 			ac.mu.Lock()
 			ac.printf("transport exiting: %v", err)
@@ -1084,7 +1504,7 @@ func (ac *addrConn) getReadyTransport() (transport.ClientTransport, bool) {
 	ac.mu.Unlock()
 	// Trigger idle ac to connect.
 	if idle {
-		ac.connect(false)
+		ac.connect()
 	}
 	return nil, false
 }
@@ -1097,8 +1517,11 @@ func (ac *addrConn) getReadyTransport() (transport.ClientTransport, bool) {
 func (ac *addrConn) tearDown(err error) {
 	ac.cancel()
 	ac.mu.Lock()
-	ac.curAddr = resolver.Address{}
 	defer ac.mu.Unlock()
+	if ac.state == connectivity.Shutdown {
+		return
+	}
+	ac.curAddr = resolver.Address{}
 	if err == errConnDrain && ac.transport != nil {
 		// GracefulClose(...) may be executed multiple times when
 		// i) receiving multiple GoAway frames from the server; or
@@ -1106,16 +1529,9 @@ func (ac *addrConn) tearDown(err error) {
 		// address removal and GoAway.
 		ac.transport.GracefulClose()
 	}
-	if ac.state == connectivity.Shutdown {
-		return
-	}
 	ac.state = connectivity.Shutdown
 	ac.tearDownErr = err
-	if ac.cc.balancerWrapper != nil {
-		ac.cc.balancerWrapper.handleSubConnStateChange(ac.acbw, ac.state)
-	} else {
-		ac.cc.csMgr.updateState(ac.state)
-	}
+	ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
 	if ac.events != nil {
 		ac.events.Finish()
 		ac.events = nil
@@ -1124,7 +1540,9 @@ func (ac *addrConn) tearDown(err error) {
 		close(ac.ready)
 		ac.ready = nil
 	}
-	return
+	if channelz.IsOn() {
+		channelz.RemoveEntry(ac.channelzID)
+	}
 }
 
 func (ac *addrConn) getState() connectivity.State {
@@ -1132,3 +1550,53 @@ func (ac *addrConn) getState() connectivity.State {
 	defer ac.mu.Unlock()
 	return ac.state
 }
+
+func (ac *addrConn) getCurAddr() (ret resolver.Address) {
+	ac.mu.Lock()
+	ret = ac.curAddr
+	ac.mu.Unlock()
+	return
+}
+
+func (ac *addrConn) ChannelzMetric() *channelz.ChannelInternalMetric {
+	ac.mu.Lock()
+	addr := ac.curAddr.Addr
+	ac.mu.Unlock()
+	state := ac.getState()
+	ac.czmu.RLock()
+	defer ac.czmu.RUnlock()
+	return &channelz.ChannelInternalMetric{
+		State:                    state,
+		Target:                   addr,
+		CallsStarted:             ac.callsStarted,
+		CallsSucceeded:           ac.callsSucceeded,
+		CallsFailed:              ac.callsFailed,
+		LastCallStartedTimestamp: ac.lastCallStartedTime,
+	}
+}
+
+func (ac *addrConn) incrCallsStarted() {
+	ac.czmu.Lock()
+	ac.callsStarted++
+	ac.lastCallStartedTime = time.Now()
+	ac.czmu.Unlock()
+}
+
+func (ac *addrConn) incrCallsSucceeded() {
+	ac.czmu.Lock()
+	ac.callsSucceeded++
+	ac.czmu.Unlock()
+}
+
+func (ac *addrConn) incrCallsFailed() {
+	ac.czmu.Lock()
+	ac.callsFailed++
+	ac.czmu.Unlock()
+}
+
+// ErrClientConnTimeout indicates that the ClientConn cannot establish the
+// underlying connections within the specified timeout.
+//
+// Deprecated: This error is never returned by grpc and should not be
+// referenced by users.
+var ErrClientConnTimeout = errors.New("grpc: timed out when dialing")
diff --git a/vendor/google.golang.org/grpc/codec.go b/vendor/google.golang.org/grpc/codec.go
index 905b048..1297765 100644
--- a/vendor/google.golang.org/grpc/codec.go
+++ b/vendor/google.golang.org/grpc/codec.go
@@ -19,86 +19,32 @@
 package grpc
 
 import (
-	"math"
-	"sync"
-
-	"github.com/golang/protobuf/proto"
+	"google.golang.org/grpc/encoding"
+	_ "google.golang.org/grpc/encoding/proto" // to register the Codec for "proto"
 )
 
+// baseCodec contains the functionality of both Codec and encoding.Codec, but
+// omits the name/string, which vary between the two and are not needed for
+// anything besides the registry in the encoding package.
+type baseCodec interface {
+	Marshal(v interface{}) ([]byte, error)
+	Unmarshal(data []byte, v interface{}) error
+}
+
+var _ baseCodec = Codec(nil)
+var _ baseCodec = encoding.Codec(nil)
+
 // Codec defines the interface gRPC uses to encode and decode messages.
 // Note that implementations of this interface must be thread safe;
 // a Codec's methods can be called from concurrent goroutines.
+//
+// Deprecated: use encoding.Codec instead.
 type Codec interface {
 	// Marshal returns the wire format of v.
 	Marshal(v interface{}) ([]byte, error)
 	// Unmarshal parses the wire format into v.
 	Unmarshal(data []byte, v interface{}) error
-	// String returns the name of the Codec implementation. The returned
-	// string will be used as part of content type in transmission.
+	// String returns the name of the Codec implementation.  This is unused by
+	// gRPC.
 	String() string
 }
-
-// protoCodec is a Codec implementation with protobuf. It is the default codec for gRPC.
-type protoCodec struct {
-}
-
-type cachedProtoBuffer struct {
-	lastMarshaledSize uint32
-	proto.Buffer
-}
-
-func capToMaxInt32(val int) uint32 {
-	if val > math.MaxInt32 {
-		return uint32(math.MaxInt32)
-	}
-	return uint32(val)
-}
-
-func (p protoCodec) marshal(v interface{}, cb *cachedProtoBuffer) ([]byte, error) {
-	protoMsg := v.(proto.Message)
-	newSlice := make([]byte, 0, cb.lastMarshaledSize)
-
-	cb.SetBuf(newSlice)
-	cb.Reset()
-	if err := cb.Marshal(protoMsg); err != nil {
-		return nil, err
-	}
-	out := cb.Bytes()
-	cb.lastMarshaledSize = capToMaxInt32(len(out))
-	return out, nil
-}
-
-func (p protoCodec) Marshal(v interface{}) ([]byte, error) {
-	cb := protoBufferPool.Get().(*cachedProtoBuffer)
-	out, err := p.marshal(v, cb)
-
-	// put back buffer and lose the ref to the slice
-	cb.SetBuf(nil)
-	protoBufferPool.Put(cb)
-	return out, err
-}
-
-func (p protoCodec) Unmarshal(data []byte, v interface{}) error {
-	cb := protoBufferPool.Get().(*cachedProtoBuffer)
-	cb.SetBuf(data)
-	v.(proto.Message).Reset()
-	err := cb.Unmarshal(v.(proto.Message))
-	cb.SetBuf(nil)
-	protoBufferPool.Put(cb)
-	return err
-}
-
-func (protoCodec) String() string {
-	return "proto"
-}
-
-var (
-	protoBufferPool = &sync.Pool{
-		New: func() interface{} {
-			return &cachedProtoBuffer{
-				Buffer:            proto.Buffer{},
-				lastMarshaledSize: 16,
-			}
-		},
-	}
-)
diff --git a/vendor/google.golang.org/grpc/codes/code_string.go b/vendor/google.golang.org/grpc/codes/code_string.go
index 2598370..0b206a5 100644
--- a/vendor/google.golang.org/grpc/codes/code_string.go
+++ b/vendor/google.golang.org/grpc/codes/code_string.go
@@ -1,16 +1,62 @@
-// Code generated by "stringer -type=Code"; DO NOT EDIT.
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
 
 package codes
 
-import "fmt"
+import "strconv"
 
-const _Code_name = "OKCanceledUnknownInvalidArgumentDeadlineExceededNotFoundAlreadyExistsPermissionDeniedResourceExhaustedFailedPreconditionAbortedOutOfRangeUnimplementedInternalUnavailableDataLossUnauthenticated"
-
-var _Code_index = [...]uint8{0, 2, 10, 17, 32, 48, 56, 69, 85, 102, 120, 127, 137, 150, 158, 169, 177, 192}
-
-func (i Code) String() string {
-	if i >= Code(len(_Code_index)-1) {
-		return fmt.Sprintf("Code(%d)", i)
+func (c Code) String() string {
+	switch c {
+	case OK:
+		return "OK"
+	case Canceled:
+		return "Canceled"
+	case Unknown:
+		return "Unknown"
+	case InvalidArgument:
+		return "InvalidArgument"
+	case DeadlineExceeded:
+		return "DeadlineExceeded"
+	case NotFound:
+		return "NotFound"
+	case AlreadyExists:
+		return "AlreadyExists"
+	case PermissionDenied:
+		return "PermissionDenied"
+	case ResourceExhausted:
+		return "ResourceExhausted"
+	case FailedPrecondition:
+		return "FailedPrecondition"
+	case Aborted:
+		return "Aborted"
+	case OutOfRange:
+		return "OutOfRange"
+	case Unimplemented:
+		return "Unimplemented"
+	case Internal:
+		return "Internal"
+	case Unavailable:
+		return "Unavailable"
+	case DataLoss:
+		return "DataLoss"
+	case Unauthenticated:
+		return "Unauthenticated"
+	default:
+		return "Code(" + strconv.FormatInt(int64(c), 10) + ")"
 	}
-	return _Code_name[_Code_index[i]:_Code_index[i+1]]
 }
diff --git a/vendor/google.golang.org/grpc/codes/codes.go b/vendor/google.golang.org/grpc/codes/codes.go
index 21e7733..d9b9d57 100644
--- a/vendor/google.golang.org/grpc/codes/codes.go
+++ b/vendor/google.golang.org/grpc/codes/codes.go
@@ -20,11 +20,14 @@
 // consistent across various languages.
 package codes // import "google.golang.org/grpc/codes"
 
+import (
+	"fmt"
+	"strconv"
+)
+
 // A Code is an unsigned 32-bit error code as defined in the gRPC spec.
 type Code uint32
 
-//go:generate stringer -type=Code
-
 const (
 	// OK is returned on success.
 	OK Code = 0
@@ -32,9 +35,9 @@ const (
 	// Canceled indicates the operation was canceled (typically by the caller).
 	Canceled Code = 1
 
-	// Unknown error.  An example of where this error may be returned is
+	// Unknown error. An example of where this error may be returned is
 	// if a Status value received from another address space belongs to
-	// an error-space that is not known in this address space.  Also
+	// an error-space that is not known in this address space. Also
 	// errors raised by APIs that do not return enough error information
 	// may be converted to this error.
 	Unknown Code = 2
@@ -63,15 +66,11 @@ const (
 	// PermissionDenied indicates the caller does not have permission to
 	// execute the specified operation. It must not be used for rejections
 	// caused by exhausting some resource (use ResourceExhausted
-	// instead for those errors).  It must not be
+	// instead for those errors). It must not be
 	// used if the caller cannot be identified (use Unauthenticated
 	// instead for those errors).
 	PermissionDenied Code = 7
 
-	// Unauthenticated indicates the request does not have valid
-	// authentication credentials for the operation.
-	Unauthenticated Code = 16
-
 	// ResourceExhausted indicates some resource has been exhausted, perhaps
 	// a per-user quota, or perhaps the entire file system is out of space.
 	ResourceExhausted Code = 8
@@ -87,7 +86,7 @@ const (
 	//  (b) Use Aborted if the client should retry at a higher-level
 	//      (e.g., restarting a read-modify-write sequence).
 	//  (c) Use FailedPrecondition if the client should not retry until
-	//      the system state has been explicitly fixed.  E.g., if an "rmdir"
+	//      the system state has been explicitly fixed. E.g., if an "rmdir"
 	//      fails because the directory is non-empty, FailedPrecondition
 	//      should be returned since the client should not retry unless
 	//      they have first fixed up the directory by deleting files from it.
@@ -116,7 +115,7 @@ const (
 	// file size.
 	//
 	// There is a fair bit of overlap between FailedPrecondition and
-	// OutOfRange.  We recommend using OutOfRange (the more specific
+	// OutOfRange. We recommend using OutOfRange (the more specific
 	// error) when it applies so that callers who are iterating through
 	// a space can easily look for an OutOfRange error to detect when
 	// they are done.
@@ -126,8 +125,8 @@ const (
 	// supported/enabled in this service.
 	Unimplemented Code = 12
 
-	// Internal errors.  Means some invariants expected by underlying
-	// system has been broken.  If you see one of these errors,
+	// Internal errors. Means some invariants expected by underlying
+	// system has been broken. If you see one of these errors,
 	// something is very broken.
 	Internal Code = 13
 
@@ -141,4 +140,58 @@ const (
 
 	// DataLoss indicates unrecoverable data loss or corruption.
 	DataLoss Code = 15
+
+	// Unauthenticated indicates the request does not have valid
+	// authentication credentials for the operation.
+	Unauthenticated Code = 16
+
+	_maxCode = 17
 )
+
+var strToCode = map[string]Code{
+	`"OK"`: OK,
+	`"CANCELLED"`:/* [sic] */ Canceled,
+	`"UNKNOWN"`:             Unknown,
+	`"INVALID_ARGUMENT"`:    InvalidArgument,
+	`"DEADLINE_EXCEEDED"`:   DeadlineExceeded,
+	`"NOT_FOUND"`:           NotFound,
+	`"ALREADY_EXISTS"`:      AlreadyExists,
+	`"PERMISSION_DENIED"`:   PermissionDenied,
+	`"RESOURCE_EXHAUSTED"`:  ResourceExhausted,
+	`"FAILED_PRECONDITION"`: FailedPrecondition,
+	`"ABORTED"`:             Aborted,
+	`"OUT_OF_RANGE"`:        OutOfRange,
+	`"UNIMPLEMENTED"`:       Unimplemented,
+	`"INTERNAL"`:            Internal,
+	`"UNAVAILABLE"`:         Unavailable,
+	`"DATA_LOSS"`:           DataLoss,
+	`"UNAUTHENTICATED"`:     Unauthenticated,
+}
+
+// UnmarshalJSON unmarshals b into the Code.
+func (c *Code) UnmarshalJSON(b []byte) error {
+	// From json.Unmarshaler: By convention, to approximate the behavior of
+	// Unmarshal itself, Unmarshalers implement UnmarshalJSON([]byte("null")) as
+	// a no-op.
+	if string(b) == "null" {
+		return nil
+	}
+	if c == nil {
+		return fmt.Errorf("nil receiver passed to UnmarshalJSON")
+	}
+
+	if ci, err := strconv.ParseUint(string(b), 10, 32); err == nil {
+		if ci >= _maxCode {
+			return fmt.Errorf("invalid code: %q", ci)
+		}
+
+		*c = Code(ci)
+		return nil
+	}
+
+	if jc, ok := strToCode[string(b)]; ok {
+		*c = jc
+		return nil
+	}
+	return fmt.Errorf("invalid code: %q", string(b))
+}
diff --git a/vendor/google.golang.org/grpc/credentials/credentials.go b/vendor/google.golang.org/grpc/credentials/credentials.go
index 2475fe8..3351bf0 100644
--- a/vendor/google.golang.org/grpc/credentials/credentials.go
+++ b/vendor/google.golang.org/grpc/credentials/credentials.go
@@ -34,10 +34,8 @@ import (
 	"golang.org/x/net/context"
 )
 
-var (
-	// alpnProtoStr are the specified application level protocols for gRPC.
-	alpnProtoStr = []string{"h2"}
-)
+// alpnProtoStr are the specified application level protocols for gRPC.
+var alpnProtoStr = []string{"h2"}
 
 // PerRPCCredentials defines the common interface for the credentials which need to
 // attach security information to every RPC (e.g., oauth2).
@@ -45,8 +43,9 @@ type PerRPCCredentials interface {
 	// GetRequestMetadata gets the current request metadata, refreshing
 	// tokens if required. This should be called by the transport layer on
 	// each request, and the data should be populated in headers or other
-	// context. uri is the URI of the entry point for the request. When
-	// supported by the underlying implementation, ctx can be used for
+	// context. If a status code is returned, it will be used as the status
+	// for the RPC. uri is the URI of the entry point for the request.
+	// When supported by the underlying implementation, ctx can be used for
 	// timeout and cancellation.
 	// TODO(zhaoq): Define the set of the qualified keys instead of leaving
 	// it as an arbitrary string.
@@ -74,11 +73,9 @@ type AuthInfo interface {
 	AuthType() string
 }
 
-var (
-	// ErrConnDispatched indicates that rawConn has been dispatched out of gRPC
-	// and the caller should not close rawConn.
-	ErrConnDispatched = errors.New("credentials: rawConn is dispatched out of gRPC")
-)
+// ErrConnDispatched indicates that rawConn has been dispatched out of gRPC
+// and the caller should not close rawConn.
+var ErrConnDispatched = errors.New("credentials: rawConn is dispatched out of gRPC")
 
 // TransportCredentials defines the common interface for all the live gRPC wire
 // protocols and supported transport security protocols (e.g., TLS, SSL).
@@ -91,10 +88,14 @@ type TransportCredentials interface {
 	// (io.EOF, context.DeadlineExceeded or err.Temporary() == true).
 	// If the returned error is a wrapper error, implementations should make sure that
 	// the error implements Temporary() to have the correct retry behaviors.
+	//
+	// If the returned net.Conn is closed, it MUST close the net.Conn provided.
 	ClientHandshake(context.Context, string, net.Conn) (net.Conn, AuthInfo, error)
 	// ServerHandshake does the authentication handshake for servers. It returns
 	// the authenticated connection and the corresponding auth information about
 	// the connection.
+	//
+	// If the returned net.Conn is closed, it MUST close the net.Conn provided.
 	ServerHandshake(net.Conn) (net.Conn, AuthInfo, error)
 	// Info provides the ProtocolInfo of this TransportCredentials.
 	Info() ProtocolInfo
@@ -131,15 +132,15 @@ func (c tlsCreds) Info() ProtocolInfo {
 	}
 }
 
-func (c *tlsCreds) ClientHandshake(ctx context.Context, addr string, rawConn net.Conn) (_ net.Conn, _ AuthInfo, err error) {
+func (c *tlsCreds) ClientHandshake(ctx context.Context, authority string, rawConn net.Conn) (_ net.Conn, _ AuthInfo, err error) {
 	// use local cfg to avoid clobbering ServerName if using multiple endpoints
 	cfg := cloneTLSConfig(c.config)
 	if cfg.ServerName == "" {
-		colonPos := strings.LastIndex(addr, ":")
+		colonPos := strings.LastIndex(authority, ":")
 		if colonPos == -1 {
-			colonPos = len(addr)
+			colonPos = len(authority)
 		}
-		cfg.ServerName = addr[:colonPos]
+		cfg.ServerName = authority[:colonPos]
 	}
 	conn := tls.Client(rawConn, cfg)
 	errChannel := make(chan error, 1)
diff --git a/vendor/google.golang.org/grpc/encoding/encoding.go b/vendor/google.golang.org/grpc/encoding/encoding.go
new file mode 100644
index 0000000..ade8b7c
--- /dev/null
+++ b/vendor/google.golang.org/grpc/encoding/encoding.go
@@ -0,0 +1,118 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package encoding defines the interface for the compressor and codec, and
+// functions to register and retrieve compressors and codecs.
+//
+// This package is EXPERIMENTAL.
+package encoding
+
+import (
+	"io"
+	"strings"
+)
+
+// Identity specifies the optional encoding for uncompressed streams.
+// It is intended for grpc internal use only.
+const Identity = "identity"
+
+// Compressor is used for compressing and decompressing when sending or
+// receiving messages.
+type Compressor interface {
+	// Compress writes the data written to wc to w after compressing it.  If an
+	// error occurs while initializing the compressor, that error is returned
+	// instead.
+	Compress(w io.Writer) (io.WriteCloser, error)
+	// Decompress reads data from r, decompresses it, and provides the
+	// uncompressed data via the returned io.Reader.  If an error occurs while
+	// initializing the decompressor, that error is returned instead.
+	Decompress(r io.Reader) (io.Reader, error)
+	// Name is the name of the compression codec and is used to set the content
+	// coding header.  The result must be static; the result cannot change
+	// between calls.
+	Name() string
+}
+
+var registeredCompressor = make(map[string]Compressor)
+
+// RegisterCompressor registers the compressor with gRPC by its name.  It can
+// be activated when sending an RPC via grpc.UseCompressor().  It will be
+// automatically accessed when receiving a message based on the content coding
+// header.  Servers also use it to send a response with the same encoding as
+// the request.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe.  If multiple Compressors are
+// registered with the same name, the one registered last will take effect.
+func RegisterCompressor(c Compressor) {
+	registeredCompressor[c.Name()] = c
+}
+
+// GetCompressor returns Compressor for the given compressor name.
+func GetCompressor(name string) Compressor {
+	return registeredCompressor[name]
+}
+
+// Codec defines the interface gRPC uses to encode and decode messages.  Note
+// that implementations of this interface must be thread safe; a Codec's
+// methods can be called from concurrent goroutines.
+type Codec interface {
+	// Marshal returns the wire format of v.
+	Marshal(v interface{}) ([]byte, error)
+	// Unmarshal parses the wire format into v.
+	Unmarshal(data []byte, v interface{}) error
+	// Name returns the name of the Codec implementation. The returned string
+	// will be used as part of content type in transmission.  The result must be
+	// static; the result cannot change between calls.
+	Name() string
+}
+
+var registeredCodecs = make(map[string]Codec)
+
+// RegisterCodec registers the provided Codec for use with all gRPC clients and
+// servers.
+//
+// The Codec will be stored and looked up by result of its Name() method, which
+// should match the content-subtype of the encoding handled by the Codec.  This
+// is case-insensitive, and is stored and looked up as lowercase.  If the
+// result of calling Name() is an empty string, RegisterCodec will panic. See
+// Content-Type on
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe.  If multiple Compressors are
+// registered with the same name, the one registered last will take effect.
+func RegisterCodec(codec Codec) {
+	if codec == nil {
+		panic("cannot register a nil Codec")
+	}
+	contentSubtype := strings.ToLower(codec.Name())
+	if contentSubtype == "" {
+		panic("cannot register Codec with empty string result for String()")
+	}
+	registeredCodecs[contentSubtype] = codec
+}
+
+// GetCodec gets a registered Codec by content-subtype, or nil if no Codec is
+// registered for the content-subtype.
+//
+// The content-subtype is expected to be lowercase.
+func GetCodec(contentSubtype string) Codec {
+	return registeredCodecs[contentSubtype]
+}
diff --git a/vendor/google.golang.org/grpc/encoding/proto/proto.go b/vendor/google.golang.org/grpc/encoding/proto/proto.go
new file mode 100644
index 0000000..66b97a6
--- /dev/null
+++ b/vendor/google.golang.org/grpc/encoding/proto/proto.go
@@ -0,0 +1,110 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package proto defines the protobuf codec. Importing this package will
+// register the codec.
+package proto
+
+import (
+	"math"
+	"sync"
+
+	"github.com/golang/protobuf/proto"
+	"google.golang.org/grpc/encoding"
+)
+
+// Name is the name registered for the proto compressor.
+const Name = "proto"
+
+func init() {
+	encoding.RegisterCodec(codec{})
+}
+
+// codec is a Codec implementation with protobuf. It is the default codec for gRPC.
+type codec struct{}
+
+type cachedProtoBuffer struct {
+	lastMarshaledSize uint32
+	proto.Buffer
+}
+
+func capToMaxInt32(val int) uint32 {
+	if val > math.MaxInt32 {
+		return uint32(math.MaxInt32)
+	}
+	return uint32(val)
+}
+
+func marshal(v interface{}, cb *cachedProtoBuffer) ([]byte, error) {
+	protoMsg := v.(proto.Message)
+	newSlice := make([]byte, 0, cb.lastMarshaledSize)
+
+	cb.SetBuf(newSlice)
+	cb.Reset()
+	if err := cb.Marshal(protoMsg); err != nil {
+		return nil, err
+	}
+	out := cb.Bytes()
+	cb.lastMarshaledSize = capToMaxInt32(len(out))
+	return out, nil
+}
+
+func (codec) Marshal(v interface{}) ([]byte, error) {
+	if pm, ok := v.(proto.Marshaler); ok {
+		// object can marshal itself, no need for buffer
+		return pm.Marshal()
+	}
+
+	cb := protoBufferPool.Get().(*cachedProtoBuffer)
+	out, err := marshal(v, cb)
+
+	// put back buffer and lose the ref to the slice
+	cb.SetBuf(nil)
+	protoBufferPool.Put(cb)
+	return out, err
+}
+
+func (codec) Unmarshal(data []byte, v interface{}) error {
+	protoMsg := v.(proto.Message)
+	protoMsg.Reset()
+
+	if pu, ok := protoMsg.(proto.Unmarshaler); ok {
+		// object can unmarshal itself, no need for buffer
+		return pu.Unmarshal(data)
+	}
+
+	cb := protoBufferPool.Get().(*cachedProtoBuffer)
+	cb.SetBuf(data)
+	err := cb.Unmarshal(protoMsg)
+	cb.SetBuf(nil)
+	protoBufferPool.Put(cb)
+	return err
+}
+
+func (codec) Name() string {
+	return Name
+}
+
+var protoBufferPool = &sync.Pool{
+	New: func() interface{} {
+		return &cachedProtoBuffer{
+			Buffer:            proto.Buffer{},
+			lastMarshaledSize: 16,
+		}
+	},
+}
diff --git a/vendor/google.golang.org/grpc/envconfig.go b/vendor/google.golang.org/grpc/envconfig.go
new file mode 100644
index 0000000..d50178e
--- /dev/null
+++ b/vendor/google.golang.org/grpc/envconfig.go
@@ -0,0 +1,37 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"os"
+	"strings"
+)
+
+const (
+	envConfigPrefix        = "GRPC_GO_"
+	envConfigStickinessStr = envConfigPrefix + "STICKINESS"
+)
+
+var (
+	envConfigStickinessOn bool
+)
+
+func init() {
+	envConfigStickinessOn = strings.EqualFold(os.Getenv(envConfigStickinessStr), "on")
+}
diff --git a/vendor/google.golang.org/grpc/go16.go b/vendor/google.golang.org/grpc/go16.go
new file mode 100644
index 0000000..535ee93
--- /dev/null
+++ b/vendor/google.golang.org/grpc/go16.go
@@ -0,0 +1,70 @@
+// +build go1.6,!go1.7
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"google.golang.org/grpc/transport"
+)
+
+// dialContext connects to the address on the named network.
+func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return (&net.Dialer{Cancel: ctx.Done()}).Dial(network, address)
+}
+
+func sendHTTPRequest(ctx context.Context, req *http.Request, conn net.Conn) error {
+	req.Cancel = ctx.Done()
+	if err := req.Write(conn); err != nil {
+		return fmt.Errorf("failed to write the HTTP request: %v", err)
+	}
+	return nil
+}
+
+// toRPCErr converts an error into an error from the status package.
+func toRPCErr(err error) error {
+	if err == nil || err == io.EOF {
+		return err
+	}
+	if _, ok := status.FromError(err); ok {
+		return err
+	}
+	switch e := err.(type) {
+	case transport.StreamError:
+		return status.Error(e.Code, e.Desc)
+	case transport.ConnectionError:
+		return status.Error(codes.Unavailable, e.Desc)
+	default:
+		switch err {
+		case context.DeadlineExceeded:
+			return status.Error(codes.DeadlineExceeded, err.Error())
+		case context.Canceled:
+			return status.Error(codes.Canceled, err.Error())
+		}
+	}
+	return status.Error(codes.Unknown, err.Error())
+}
diff --git a/vendor/google.golang.org/grpc/go17.go b/vendor/google.golang.org/grpc/go17.go
new file mode 100644
index 0000000..ec676a9
--- /dev/null
+++ b/vendor/google.golang.org/grpc/go17.go
@@ -0,0 +1,71 @@
+// +build go1.7
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+
+	netctx "golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"google.golang.org/grpc/transport"
+)
+
+// dialContext connects to the address on the named network.
+func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return (&net.Dialer{}).DialContext(ctx, network, address)
+}
+
+func sendHTTPRequest(ctx context.Context, req *http.Request, conn net.Conn) error {
+	req = req.WithContext(ctx)
+	if err := req.Write(conn); err != nil {
+		return fmt.Errorf("failed to write the HTTP request: %v", err)
+	}
+	return nil
+}
+
+// toRPCErr converts an error into an error from the status package.
+func toRPCErr(err error) error {
+	if err == nil || err == io.EOF {
+		return err
+	}
+	if _, ok := status.FromError(err); ok {
+		return err
+	}
+	switch e := err.(type) {
+	case transport.StreamError:
+		return status.Error(e.Code, e.Desc)
+	case transport.ConnectionError:
+		return status.Error(codes.Unavailable, e.Desc)
+	default:
+		switch err {
+		case context.DeadlineExceeded, netctx.DeadlineExceeded:
+			return status.Error(codes.DeadlineExceeded, err.Error())
+		case context.Canceled, netctx.Canceled:
+			return status.Error(codes.Canceled, err.Error())
+		}
+	}
+	return status.Error(codes.Unknown, err.Error())
+}
diff --git a/vendor/google.golang.org/grpc/grpclb.go b/vendor/google.golang.org/grpc/grpclb.go
deleted file mode 100644
index db56ff3..0000000
--- a/vendor/google.golang.org/grpc/grpclb.go
+++ /dev/null
@@ -1,704 +0,0 @@
-/*
- *
- * Copyright 2016 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package grpc
-
-import (
-	"errors"
-	"fmt"
-	"math/rand"
-	"net"
-	"sync"
-	"time"
-
-	"golang.org/x/net/context"
-	"google.golang.org/grpc/codes"
-	lbmpb "google.golang.org/grpc/grpclb/grpc_lb_v1/messages"
-	"google.golang.org/grpc/grpclog"
-	"google.golang.org/grpc/metadata"
-	"google.golang.org/grpc/naming"
-)
-
-// Client API for LoadBalancer service.
-// Mostly copied from generated pb.go file.
-// To avoid circular dependency.
-type loadBalancerClient struct {
-	cc *ClientConn
-}
-
-func (c *loadBalancerClient) BalanceLoad(ctx context.Context, opts ...CallOption) (*balanceLoadClientStream, error) {
-	desc := &StreamDesc{
-		StreamName:    "BalanceLoad",
-		ServerStreams: true,
-		ClientStreams: true,
-	}
-	stream, err := NewClientStream(ctx, desc, c.cc, "/grpc.lb.v1.LoadBalancer/BalanceLoad", opts...)
-	if err != nil {
-		return nil, err
-	}
-	x := &balanceLoadClientStream{stream}
-	return x, nil
-}
-
-type balanceLoadClientStream struct {
-	ClientStream
-}
-
-func (x *balanceLoadClientStream) Send(m *lbmpb.LoadBalanceRequest) error {
-	return x.ClientStream.SendMsg(m)
-}
-
-func (x *balanceLoadClientStream) Recv() (*lbmpb.LoadBalanceResponse, error) {
-	m := new(lbmpb.LoadBalanceResponse)
-	if err := x.ClientStream.RecvMsg(m); err != nil {
-		return nil, err
-	}
-	return m, nil
-}
-
-// NewGRPCLBBalancer creates a grpclb load balancer.
-func NewGRPCLBBalancer(r naming.Resolver) Balancer {
-	return &grpclbBalancer{
-		r: r,
-	}
-}
-
-type remoteBalancerInfo struct {
-	addr string
-	// the server name used for authentication with the remote LB server.
-	name string
-}
-
-// grpclbAddrInfo consists of the information of a backend server.
-type grpclbAddrInfo struct {
-	addr      Address
-	connected bool
-	// dropForRateLimiting indicates whether this particular request should be
-	// dropped by the client for rate limiting.
-	dropForRateLimiting bool
-	// dropForLoadBalancing indicates whether this particular request should be
-	// dropped by the client for load balancing.
-	dropForLoadBalancing bool
-}
-
-type grpclbBalancer struct {
-	r      naming.Resolver
-	target string
-	mu     sync.Mutex
-	seq    int // a sequence number to make sure addrCh does not get stale addresses.
-	w      naming.Watcher
-	addrCh chan []Address
-	rbs    []remoteBalancerInfo
-	addrs  []*grpclbAddrInfo
-	next   int
-	waitCh chan struct{}
-	done   bool
-	rand   *rand.Rand
-
-	clientStats lbmpb.ClientStats
-}
-
-func (b *grpclbBalancer) watchAddrUpdates(w naming.Watcher, ch chan []remoteBalancerInfo) error {
-	updates, err := w.Next()
-	if err != nil {
-		grpclog.Warningf("grpclb: failed to get next addr update from watcher: %v", err)
-		return err
-	}
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	if b.done {
-		return ErrClientConnClosing
-	}
-	for _, update := range updates {
-		switch update.Op {
-		case naming.Add:
-			var exist bool
-			for _, v := range b.rbs {
-				// TODO: Is the same addr with different server name a different balancer?
-				if update.Addr == v.addr {
-					exist = true
-					break
-				}
-			}
-			if exist {
-				continue
-			}
-			md, ok := update.Metadata.(*naming.AddrMetadataGRPCLB)
-			if !ok {
-				// TODO: Revisit the handling here and may introduce some fallback mechanism.
-				grpclog.Errorf("The name resolution contains unexpected metadata %v", update.Metadata)
-				continue
-			}
-			switch md.AddrType {
-			case naming.Backend:
-				// TODO: Revisit the handling here and may introduce some fallback mechanism.
-				grpclog.Errorf("The name resolution does not give grpclb addresses")
-				continue
-			case naming.GRPCLB:
-				b.rbs = append(b.rbs, remoteBalancerInfo{
-					addr: update.Addr,
-					name: md.ServerName,
-				})
-			default:
-				grpclog.Errorf("Received unknow address type %d", md.AddrType)
-				continue
-			}
-		case naming.Delete:
-			for i, v := range b.rbs {
-				if update.Addr == v.addr {
-					copy(b.rbs[i:], b.rbs[i+1:])
-					b.rbs = b.rbs[:len(b.rbs)-1]
-					break
-				}
-			}
-		default:
-			grpclog.Errorf("Unknown update.Op %v", update.Op)
-		}
-	}
-	// TODO: Fall back to the basic round-robin load balancing if the resulting address is
-	// not a load balancer.
-	select {
-	case <-ch:
-	default:
-	}
-	ch <- b.rbs
-	return nil
-}
-
-func convertDuration(d *lbmpb.Duration) time.Duration {
-	if d == nil {
-		return 0
-	}
-	return time.Duration(d.Seconds)*time.Second + time.Duration(d.Nanos)*time.Nanosecond
-}
-
-func (b *grpclbBalancer) processServerList(l *lbmpb.ServerList, seq int) {
-	if l == nil {
-		return
-	}
-	servers := l.GetServers()
-	var (
-		sl    []*grpclbAddrInfo
-		addrs []Address
-	)
-	for _, s := range servers {
-		md := metadata.Pairs("lb-token", s.LoadBalanceToken)
-		ip := net.IP(s.IpAddress)
-		ipStr := ip.String()
-		if ip.To4() == nil {
-			// Add square brackets to ipv6 addresses, otherwise net.Dial() and
-			// net.SplitHostPort() will return too many colons error.
-			ipStr = fmt.Sprintf("[%s]", ipStr)
-		}
-		addr := Address{
-			Addr:     fmt.Sprintf("%s:%d", ipStr, s.Port),
-			Metadata: &md,
-		}
-		sl = append(sl, &grpclbAddrInfo{
-			addr:                 addr,
-			dropForRateLimiting:  s.DropForRateLimiting,
-			dropForLoadBalancing: s.DropForLoadBalancing,
-		})
-		addrs = append(addrs, addr)
-	}
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	if b.done || seq < b.seq {
-		return
-	}
-	if len(sl) > 0 {
-		// reset b.next to 0 when replacing the server list.
-		b.next = 0
-		b.addrs = sl
-		b.addrCh <- addrs
-	}
-	return
-}
-
-func (b *grpclbBalancer) sendLoadReport(s *balanceLoadClientStream, interval time.Duration, done <-chan struct{}) {
-	ticker := time.NewTicker(interval)
-	defer ticker.Stop()
-	for {
-		select {
-		case <-ticker.C:
-		case <-done:
-			return
-		}
-		b.mu.Lock()
-		stats := b.clientStats
-		b.clientStats = lbmpb.ClientStats{} // Clear the stats.
-		b.mu.Unlock()
-		t := time.Now()
-		stats.Timestamp = &lbmpb.Timestamp{
-			Seconds: t.Unix(),
-			Nanos:   int32(t.Nanosecond()),
-		}
-		if err := s.Send(&lbmpb.LoadBalanceRequest{
-			LoadBalanceRequestType: &lbmpb.LoadBalanceRequest_ClientStats{
-				ClientStats: &stats,
-			},
-		}); err != nil {
-			grpclog.Errorf("grpclb: failed to send load report: %v", err)
-			return
-		}
-	}
-}
-
-func (b *grpclbBalancer) callRemoteBalancer(lbc *loadBalancerClient, seq int) (retry bool) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-	stream, err := lbc.BalanceLoad(ctx)
-	if err != nil {
-		grpclog.Errorf("grpclb: failed to perform RPC to the remote balancer %v", err)
-		return
-	}
-	b.mu.Lock()
-	if b.done {
-		b.mu.Unlock()
-		return
-	}
-	b.mu.Unlock()
-	initReq := &lbmpb.LoadBalanceRequest{
-		LoadBalanceRequestType: &lbmpb.LoadBalanceRequest_InitialRequest{
-			InitialRequest: &lbmpb.InitialLoadBalanceRequest{
-				Name: b.target,
-			},
-		},
-	}
-	if err := stream.Send(initReq); err != nil {
-		grpclog.Errorf("grpclb: failed to send init request: %v", err)
-		// TODO: backoff on retry?
-		return true
-	}
-	reply, err := stream.Recv()
-	if err != nil {
-		grpclog.Errorf("grpclb: failed to recv init response: %v", err)
-		// TODO: backoff on retry?
-		return true
-	}
-	initResp := reply.GetInitialResponse()
-	if initResp == nil {
-		grpclog.Errorf("grpclb: reply from remote balancer did not include initial response.")
-		return
-	}
-	// TODO: Support delegation.
-	if initResp.LoadBalancerDelegate != "" {
-		// delegation
-		grpclog.Errorf("TODO: Delegation is not supported yet.")
-		return
-	}
-	streamDone := make(chan struct{})
-	defer close(streamDone)
-	b.mu.Lock()
-	b.clientStats = lbmpb.ClientStats{} // Clear client stats.
-	b.mu.Unlock()
-	if d := convertDuration(initResp.ClientStatsReportInterval); d > 0 {
-		go b.sendLoadReport(stream, d, streamDone)
-	}
-	// Retrieve the server list.
-	for {
-		reply, err := stream.Recv()
-		if err != nil {
-			grpclog.Errorf("grpclb: failed to recv server list: %v", err)
-			break
-		}
-		b.mu.Lock()
-		if b.done || seq < b.seq {
-			b.mu.Unlock()
-			return
-		}
-		b.seq++ // tick when receiving a new list of servers.
-		seq = b.seq
-		b.mu.Unlock()
-		if serverList := reply.GetServerList(); serverList != nil {
-			b.processServerList(serverList, seq)
-		}
-	}
-	return true
-}
-
-func (b *grpclbBalancer) Start(target string, config BalancerConfig) error {
-	b.rand = rand.New(rand.NewSource(time.Now().Unix()))
-	// TODO: Fall back to the basic direct connection if there is no name resolver.
-	if b.r == nil {
-		return errors.New("there is no name resolver installed")
-	}
-	b.target = target
-	b.mu.Lock()
-	if b.done {
-		b.mu.Unlock()
-		return ErrClientConnClosing
-	}
-	b.addrCh = make(chan []Address)
-	w, err := b.r.Resolve(target)
-	if err != nil {
-		b.mu.Unlock()
-		grpclog.Errorf("grpclb: failed to resolve address: %v, err: %v", target, err)
-		return err
-	}
-	b.w = w
-	b.mu.Unlock()
-	balancerAddrsCh := make(chan []remoteBalancerInfo, 1)
-	// Spawn a goroutine to monitor the name resolution of remote load balancer.
-	go func() {
-		for {
-			if err := b.watchAddrUpdates(w, balancerAddrsCh); err != nil {
-				grpclog.Warningf("grpclb: the naming watcher stops working due to %v.\n", err)
-				close(balancerAddrsCh)
-				return
-			}
-		}
-	}()
-	// Spawn a goroutine to talk to the remote load balancer.
-	go func() {
-		var (
-			cc *ClientConn
-			// ccError is closed when there is an error in the current cc.
-			// A new rb should be picked from rbs and connected.
-			ccError chan struct{}
-			rb      *remoteBalancerInfo
-			rbs     []remoteBalancerInfo
-			rbIdx   int
-		)
-
-		defer func() {
-			if ccError != nil {
-				select {
-				case <-ccError:
-				default:
-					close(ccError)
-				}
-			}
-			if cc != nil {
-				cc.Close()
-			}
-		}()
-
-		for {
-			var ok bool
-			select {
-			case rbs, ok = <-balancerAddrsCh:
-				if !ok {
-					return
-				}
-				foundIdx := -1
-				if rb != nil {
-					for i, trb := range rbs {
-						if trb == *rb {
-							foundIdx = i
-							break
-						}
-					}
-				}
-				if foundIdx >= 0 {
-					if foundIdx >= 1 {
-						// Move the address in use to the beginning of the list.
-						b.rbs[0], b.rbs[foundIdx] = b.rbs[foundIdx], b.rbs[0]
-						rbIdx = 0
-					}
-					continue // If found, don't dial new cc.
-				} else if len(rbs) > 0 {
-					// Pick a random one from the list, instead of always using the first one.
-					if l := len(rbs); l > 1 && rb != nil {
-						tmpIdx := b.rand.Intn(l - 1)
-						b.rbs[0], b.rbs[tmpIdx] = b.rbs[tmpIdx], b.rbs[0]
-					}
-					rbIdx = 0
-					rb = &rbs[0]
-				} else {
-					// foundIdx < 0 && len(rbs) <= 0.
-					rb = nil
-				}
-			case <-ccError:
-				ccError = nil
-				if rbIdx < len(rbs)-1 {
-					rbIdx++
-					rb = &rbs[rbIdx]
-				} else {
-					rb = nil
-				}
-			}
-
-			if rb == nil {
-				continue
-			}
-
-			if cc != nil {
-				cc.Close()
-			}
-			// Talk to the remote load balancer to get the server list.
-			var (
-				err   error
-				dopts []DialOption
-			)
-			if creds := config.DialCreds; creds != nil {
-				if rb.name != "" {
-					if err := creds.OverrideServerName(rb.name); err != nil {
-						grpclog.Warningf("grpclb: failed to override the server name in the credentials: %v", err)
-						continue
-					}
-				}
-				dopts = append(dopts, WithTransportCredentials(creds))
-			} else {
-				dopts = append(dopts, WithInsecure())
-			}
-			if dialer := config.Dialer; dialer != nil {
-				// WithDialer takes a different type of function, so we instead use a special DialOption here.
-				dopts = append(dopts, func(o *dialOptions) { o.copts.Dialer = dialer })
-			}
-			dopts = append(dopts, WithBlock())
-			ccError = make(chan struct{})
-			ctx, cancel := context.WithTimeout(context.Background(), time.Second)
-			cc, err = DialContext(ctx, rb.addr, dopts...)
-			cancel()
-			if err != nil {
-				grpclog.Warningf("grpclb: failed to setup a connection to the remote balancer %v: %v", rb.addr, err)
-				close(ccError)
-				continue
-			}
-			b.mu.Lock()
-			b.seq++ // tick when getting a new balancer address
-			seq := b.seq
-			b.next = 0
-			b.mu.Unlock()
-			go func(cc *ClientConn, ccError chan struct{}) {
-				lbc := &loadBalancerClient{cc}
-				b.callRemoteBalancer(lbc, seq)
-				cc.Close()
-				select {
-				case <-ccError:
-				default:
-					close(ccError)
-				}
-			}(cc, ccError)
-		}
-	}()
-	return nil
-}
-
-func (b *grpclbBalancer) down(addr Address, err error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	for _, a := range b.addrs {
-		if addr == a.addr {
-			a.connected = false
-			break
-		}
-	}
-}
-
-func (b *grpclbBalancer) Up(addr Address) func(error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	if b.done {
-		return nil
-	}
-	var cnt int
-	for _, a := range b.addrs {
-		if a.addr == addr {
-			if a.connected {
-				return nil
-			}
-			a.connected = true
-		}
-		if a.connected && !a.dropForRateLimiting && !a.dropForLoadBalancing {
-			cnt++
-		}
-	}
-	// addr is the only one which is connected. Notify the Get() callers who are blocking.
-	if cnt == 1 && b.waitCh != nil {
-		close(b.waitCh)
-		b.waitCh = nil
-	}
-	return func(err error) {
-		b.down(addr, err)
-	}
-}
-
-func (b *grpclbBalancer) Get(ctx context.Context, opts BalancerGetOptions) (addr Address, put func(), err error) {
-	var ch chan struct{}
-	b.mu.Lock()
-	if b.done {
-		b.mu.Unlock()
-		err = ErrClientConnClosing
-		return
-	}
-	seq := b.seq
-
-	defer func() {
-		if err != nil {
-			return
-		}
-		put = func() {
-			s, ok := rpcInfoFromContext(ctx)
-			if !ok {
-				return
-			}
-			b.mu.Lock()
-			defer b.mu.Unlock()
-			if b.done || seq < b.seq {
-				return
-			}
-			b.clientStats.NumCallsFinished++
-			if !s.bytesSent {
-				b.clientStats.NumCallsFinishedWithClientFailedToSend++
-			} else if s.bytesReceived {
-				b.clientStats.NumCallsFinishedKnownReceived++
-			}
-		}
-	}()
-
-	b.clientStats.NumCallsStarted++
-	if len(b.addrs) > 0 {
-		if b.next >= len(b.addrs) {
-			b.next = 0
-		}
-		next := b.next
-		for {
-			a := b.addrs[next]
-			next = (next + 1) % len(b.addrs)
-			if a.connected {
-				if !a.dropForRateLimiting && !a.dropForLoadBalancing {
-					addr = a.addr
-					b.next = next
-					b.mu.Unlock()
-					return
-				}
-				if !opts.BlockingWait {
-					b.next = next
-					if a.dropForLoadBalancing {
-						b.clientStats.NumCallsFinished++
-						b.clientStats.NumCallsFinishedWithDropForLoadBalancing++
-					} else if a.dropForRateLimiting {
-						b.clientStats.NumCallsFinished++
-						b.clientStats.NumCallsFinishedWithDropForRateLimiting++
-					}
-					b.mu.Unlock()
-					err = Errorf(codes.Unavailable, "%s drops requests", a.addr.Addr)
-					return
-				}
-			}
-			if next == b.next {
-				// Has iterated all the possible address but none is connected.
-				break
-			}
-		}
-	}
-	if !opts.BlockingWait {
-		b.clientStats.NumCallsFinished++
-		b.clientStats.NumCallsFinishedWithClientFailedToSend++
-		b.mu.Unlock()
-		err = Errorf(codes.Unavailable, "there is no address available")
-		return
-	}
-	// Wait on b.waitCh for non-failfast RPCs.
-	if b.waitCh == nil {
-		ch = make(chan struct{})
-		b.waitCh = ch
-	} else {
-		ch = b.waitCh
-	}
-	b.mu.Unlock()
-	for {
-		select {
-		case <-ctx.Done():
-			b.mu.Lock()
-			b.clientStats.NumCallsFinished++
-			b.clientStats.NumCallsFinishedWithClientFailedToSend++
-			b.mu.Unlock()
-			err = ctx.Err()
-			return
-		case <-ch:
-			b.mu.Lock()
-			if b.done {
-				b.clientStats.NumCallsFinished++
-				b.clientStats.NumCallsFinishedWithClientFailedToSend++
-				b.mu.Unlock()
-				err = ErrClientConnClosing
-				return
-			}
-
-			if len(b.addrs) > 0 {
-				if b.next >= len(b.addrs) {
-					b.next = 0
-				}
-				next := b.next
-				for {
-					a := b.addrs[next]
-					next = (next + 1) % len(b.addrs)
-					if a.connected {
-						if !a.dropForRateLimiting && !a.dropForLoadBalancing {
-							addr = a.addr
-							b.next = next
-							b.mu.Unlock()
-							return
-						}
-						if !opts.BlockingWait {
-							b.next = next
-							if a.dropForLoadBalancing {
-								b.clientStats.NumCallsFinished++
-								b.clientStats.NumCallsFinishedWithDropForLoadBalancing++
-							} else if a.dropForRateLimiting {
-								b.clientStats.NumCallsFinished++
-								b.clientStats.NumCallsFinishedWithDropForRateLimiting++
-							}
-							b.mu.Unlock()
-							err = Errorf(codes.Unavailable, "drop requests for the addreess %s", a.addr.Addr)
-							return
-						}
-					}
-					if next == b.next {
-						// Has iterated all the possible address but none is connected.
-						break
-					}
-				}
-			}
-			// The newly added addr got removed by Down() again.
-			if b.waitCh == nil {
-				ch = make(chan struct{})
-				b.waitCh = ch
-			} else {
-				ch = b.waitCh
-			}
-			b.mu.Unlock()
-		}
-	}
-}
-
-func (b *grpclbBalancer) Notify() <-chan []Address {
-	return b.addrCh
-}
-
-func (b *grpclbBalancer) Close() error {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	if b.done {
-		return errBalancerClosed
-	}
-	b.done = true
-	if b.waitCh != nil {
-		close(b.waitCh)
-	}
-	if b.addrCh != nil {
-		close(b.addrCh)
-	}
-	if b.w != nil {
-		b.w.Close()
-	}
-	return nil
-}
diff --git a/vendor/google.golang.org/grpc/grpclb/grpc_lb_v1/messages/messages.pb.go b/vendor/google.golang.org/grpc/grpclb/grpc_lb_v1/messages/messages.pb.go
deleted file mode 100644
index f4a2712..0000000
--- a/vendor/google.golang.org/grpc/grpclb/grpc_lb_v1/messages/messages.pb.go
+++ /dev/null
@@ -1,615 +0,0 @@
-// Code generated by protoc-gen-go. DO NOT EDIT.
-// source: grpc_lb_v1/messages/messages.proto
-
-/*
-Package messages is a generated protocol buffer package.
-
-It is generated from these files:
-	grpc_lb_v1/messages/messages.proto
-
-It has these top-level messages:
-	Duration
-	Timestamp
-	LoadBalanceRequest
-	InitialLoadBalanceRequest
-	ClientStats
-	LoadBalanceResponse
-	InitialLoadBalanceResponse
-	ServerList
-	Server
-*/
-package messages
-
-import proto "github.com/golang/protobuf/proto"
-import fmt "fmt"
-import math "math"
-
-// Reference imports to suppress errors if they are not otherwise used.
-var _ = proto.Marshal
-var _ = fmt.Errorf
-var _ = math.Inf
-
-// This is a compile-time assertion to ensure that this generated file
-// is compatible with the proto package it is being compiled against.
-// A compilation error at this line likely means your copy of the
-// proto package needs to be updated.
-const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package
-
-type Duration struct {
-	// Signed seconds of the span of time. Must be from -315,576,000,000
-	// to +315,576,000,000 inclusive.
-	Seconds int64 `protobuf:"varint,1,opt,name=seconds" json:"seconds,omitempty"`
-	// Signed fractions of a second at nanosecond resolution of the span
-	// of time. Durations less than one second are represented with a 0
-	// `seconds` field and a positive or negative `nanos` field. For durations
-	// of one second or more, a non-zero value for the `nanos` field must be
-	// of the same sign as the `seconds` field. Must be from -999,999,999
-	// to +999,999,999 inclusive.
-	Nanos int32 `protobuf:"varint,2,opt,name=nanos" json:"nanos,omitempty"`
-}
-
-func (m *Duration) Reset()                    { *m = Duration{} }
-func (m *Duration) String() string            { return proto.CompactTextString(m) }
-func (*Duration) ProtoMessage()               {}
-func (*Duration) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{0} }
-
-func (m *Duration) GetSeconds() int64 {
-	if m != nil {
-		return m.Seconds
-	}
-	return 0
-}
-
-func (m *Duration) GetNanos() int32 {
-	if m != nil {
-		return m.Nanos
-	}
-	return 0
-}
-
-type Timestamp struct {
-	// Represents seconds of UTC time since Unix epoch
-	// 1970-01-01T00:00:00Z. Must be from 0001-01-01T00:00:00Z to
-	// 9999-12-31T23:59:59Z inclusive.
-	Seconds int64 `protobuf:"varint,1,opt,name=seconds" json:"seconds,omitempty"`
-	// Non-negative fractions of a second at nanosecond resolution. Negative
-	// second values with fractions must still have non-negative nanos values
-	// that count forward in time. Must be from 0 to 999,999,999
-	// inclusive.
-	Nanos int32 `protobuf:"varint,2,opt,name=nanos" json:"nanos,omitempty"`
-}
-
-func (m *Timestamp) Reset()                    { *m = Timestamp{} }
-func (m *Timestamp) String() string            { return proto.CompactTextString(m) }
-func (*Timestamp) ProtoMessage()               {}
-func (*Timestamp) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{1} }
-
-func (m *Timestamp) GetSeconds() int64 {
-	if m != nil {
-		return m.Seconds
-	}
-	return 0
-}
-
-func (m *Timestamp) GetNanos() int32 {
-	if m != nil {
-		return m.Nanos
-	}
-	return 0
-}
-
-type LoadBalanceRequest struct {
-	// Types that are valid to be assigned to LoadBalanceRequestType:
-	//	*LoadBalanceRequest_InitialRequest
-	//	*LoadBalanceRequest_ClientStats
-	LoadBalanceRequestType isLoadBalanceRequest_LoadBalanceRequestType `protobuf_oneof:"load_balance_request_type"`
-}
-
-func (m *LoadBalanceRequest) Reset()                    { *m = LoadBalanceRequest{} }
-func (m *LoadBalanceRequest) String() string            { return proto.CompactTextString(m) }
-func (*LoadBalanceRequest) ProtoMessage()               {}
-func (*LoadBalanceRequest) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{2} }
-
-type isLoadBalanceRequest_LoadBalanceRequestType interface {
-	isLoadBalanceRequest_LoadBalanceRequestType()
-}
-
-type LoadBalanceRequest_InitialRequest struct {
-	InitialRequest *InitialLoadBalanceRequest `protobuf:"bytes,1,opt,name=initial_request,json=initialRequest,oneof"`
-}
-type LoadBalanceRequest_ClientStats struct {
-	ClientStats *ClientStats `protobuf:"bytes,2,opt,name=client_stats,json=clientStats,oneof"`
-}
-
-func (*LoadBalanceRequest_InitialRequest) isLoadBalanceRequest_LoadBalanceRequestType() {}
-func (*LoadBalanceRequest_ClientStats) isLoadBalanceRequest_LoadBalanceRequestType()    {}
-
-func (m *LoadBalanceRequest) GetLoadBalanceRequestType() isLoadBalanceRequest_LoadBalanceRequestType {
-	if m != nil {
-		return m.LoadBalanceRequestType
-	}
-	return nil
-}
-
-func (m *LoadBalanceRequest) GetInitialRequest() *InitialLoadBalanceRequest {
-	if x, ok := m.GetLoadBalanceRequestType().(*LoadBalanceRequest_InitialRequest); ok {
-		return x.InitialRequest
-	}
-	return nil
-}
-
-func (m *LoadBalanceRequest) GetClientStats() *ClientStats {
-	if x, ok := m.GetLoadBalanceRequestType().(*LoadBalanceRequest_ClientStats); ok {
-		return x.ClientStats
-	}
-	return nil
-}
-
-// XXX_OneofFuncs is for the internal use of the proto package.
-func (*LoadBalanceRequest) XXX_OneofFuncs() (func(msg proto.Message, b *proto.Buffer) error, func(msg proto.Message, tag, wire int, b *proto.Buffer) (bool, error), func(msg proto.Message) (n int), []interface{}) {
-	return _LoadBalanceRequest_OneofMarshaler, _LoadBalanceRequest_OneofUnmarshaler, _LoadBalanceRequest_OneofSizer, []interface{}{
-		(*LoadBalanceRequest_InitialRequest)(nil),
-		(*LoadBalanceRequest_ClientStats)(nil),
-	}
-}
-
-func _LoadBalanceRequest_OneofMarshaler(msg proto.Message, b *proto.Buffer) error {
-	m := msg.(*LoadBalanceRequest)
-	// load_balance_request_type
-	switch x := m.LoadBalanceRequestType.(type) {
-	case *LoadBalanceRequest_InitialRequest:
-		b.EncodeVarint(1<<3 | proto.WireBytes)
-		if err := b.EncodeMessage(x.InitialRequest); err != nil {
-			return err
-		}
-	case *LoadBalanceRequest_ClientStats:
-		b.EncodeVarint(2<<3 | proto.WireBytes)
-		if err := b.EncodeMessage(x.ClientStats); err != nil {
-			return err
-		}
-	case nil:
-	default:
-		return fmt.Errorf("LoadBalanceRequest.LoadBalanceRequestType has unexpected type %T", x)
-	}
-	return nil
-}
-
-func _LoadBalanceRequest_OneofUnmarshaler(msg proto.Message, tag, wire int, b *proto.Buffer) (bool, error) {
-	m := msg.(*LoadBalanceRequest)
-	switch tag {
-	case 1: // load_balance_request_type.initial_request
-		if wire != proto.WireBytes {
-			return true, proto.ErrInternalBadWireType
-		}
-		msg := new(InitialLoadBalanceRequest)
-		err := b.DecodeMessage(msg)
-		m.LoadBalanceRequestType = &LoadBalanceRequest_InitialRequest{msg}
-		return true, err
-	case 2: // load_balance_request_type.client_stats
-		if wire != proto.WireBytes {
-			return true, proto.ErrInternalBadWireType
-		}
-		msg := new(ClientStats)
-		err := b.DecodeMessage(msg)
-		m.LoadBalanceRequestType = &LoadBalanceRequest_ClientStats{msg}
-		return true, err
-	default:
-		return false, nil
-	}
-}
-
-func _LoadBalanceRequest_OneofSizer(msg proto.Message) (n int) {
-	m := msg.(*LoadBalanceRequest)
-	// load_balance_request_type
-	switch x := m.LoadBalanceRequestType.(type) {
-	case *LoadBalanceRequest_InitialRequest:
-		s := proto.Size(x.InitialRequest)
-		n += proto.SizeVarint(1<<3 | proto.WireBytes)
-		n += proto.SizeVarint(uint64(s))
-		n += s
-	case *LoadBalanceRequest_ClientStats:
-		s := proto.Size(x.ClientStats)
-		n += proto.SizeVarint(2<<3 | proto.WireBytes)
-		n += proto.SizeVarint(uint64(s))
-		n += s
-	case nil:
-	default:
-		panic(fmt.Sprintf("proto: unexpected type %T in oneof", x))
-	}
-	return n
-}
-
-type InitialLoadBalanceRequest struct {
-	// Name of load balanced service (IE, balancer.service.com)
-	// length should be less than 256 bytes.
-	Name string `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
-}
-
-func (m *InitialLoadBalanceRequest) Reset()                    { *m = InitialLoadBalanceRequest{} }
-func (m *InitialLoadBalanceRequest) String() string            { return proto.CompactTextString(m) }
-func (*InitialLoadBalanceRequest) ProtoMessage()               {}
-func (*InitialLoadBalanceRequest) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{3} }
-
-func (m *InitialLoadBalanceRequest) GetName() string {
-	if m != nil {
-		return m.Name
-	}
-	return ""
-}
-
-// Contains client level statistics that are useful to load balancing. Each
-// count except the timestamp should be reset to zero after reporting the stats.
-type ClientStats struct {
-	// The timestamp of generating the report.
-	Timestamp *Timestamp `protobuf:"bytes,1,opt,name=timestamp" json:"timestamp,omitempty"`
-	// The total number of RPCs that started.
-	NumCallsStarted int64 `protobuf:"varint,2,opt,name=num_calls_started,json=numCallsStarted" json:"num_calls_started,omitempty"`
-	// The total number of RPCs that finished.
-	NumCallsFinished int64 `protobuf:"varint,3,opt,name=num_calls_finished,json=numCallsFinished" json:"num_calls_finished,omitempty"`
-	// The total number of RPCs that were dropped by the client because of rate
-	// limiting.
-	NumCallsFinishedWithDropForRateLimiting int64 `protobuf:"varint,4,opt,name=num_calls_finished_with_drop_for_rate_limiting,json=numCallsFinishedWithDropForRateLimiting" json:"num_calls_finished_with_drop_for_rate_limiting,omitempty"`
-	// The total number of RPCs that were dropped by the client because of load
-	// balancing.
-	NumCallsFinishedWithDropForLoadBalancing int64 `protobuf:"varint,5,opt,name=num_calls_finished_with_drop_for_load_balancing,json=numCallsFinishedWithDropForLoadBalancing" json:"num_calls_finished_with_drop_for_load_balancing,omitempty"`
-	// The total number of RPCs that failed to reach a server except dropped RPCs.
-	NumCallsFinishedWithClientFailedToSend int64 `protobuf:"varint,6,opt,name=num_calls_finished_with_client_failed_to_send,json=numCallsFinishedWithClientFailedToSend" json:"num_calls_finished_with_client_failed_to_send,omitempty"`
-	// The total number of RPCs that finished and are known to have been received
-	// by a server.
-	NumCallsFinishedKnownReceived int64 `protobuf:"varint,7,opt,name=num_calls_finished_known_received,json=numCallsFinishedKnownReceived" json:"num_calls_finished_known_received,omitempty"`
-}
-
-func (m *ClientStats) Reset()                    { *m = ClientStats{} }
-func (m *ClientStats) String() string            { return proto.CompactTextString(m) }
-func (*ClientStats) ProtoMessage()               {}
-func (*ClientStats) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{4} }
-
-func (m *ClientStats) GetTimestamp() *Timestamp {
-	if m != nil {
-		return m.Timestamp
-	}
-	return nil
-}
-
-func (m *ClientStats) GetNumCallsStarted() int64 {
-	if m != nil {
-		return m.NumCallsStarted
-	}
-	return 0
-}
-
-func (m *ClientStats) GetNumCallsFinished() int64 {
-	if m != nil {
-		return m.NumCallsFinished
-	}
-	return 0
-}
-
-func (m *ClientStats) GetNumCallsFinishedWithDropForRateLimiting() int64 {
-	if m != nil {
-		return m.NumCallsFinishedWithDropForRateLimiting
-	}
-	return 0
-}
-
-func (m *ClientStats) GetNumCallsFinishedWithDropForLoadBalancing() int64 {
-	if m != nil {
-		return m.NumCallsFinishedWithDropForLoadBalancing
-	}
-	return 0
-}
-
-func (m *ClientStats) GetNumCallsFinishedWithClientFailedToSend() int64 {
-	if m != nil {
-		return m.NumCallsFinishedWithClientFailedToSend
-	}
-	return 0
-}
-
-func (m *ClientStats) GetNumCallsFinishedKnownReceived() int64 {
-	if m != nil {
-		return m.NumCallsFinishedKnownReceived
-	}
-	return 0
-}
-
-type LoadBalanceResponse struct {
-	// Types that are valid to be assigned to LoadBalanceResponseType:
-	//	*LoadBalanceResponse_InitialResponse
-	//	*LoadBalanceResponse_ServerList
-	LoadBalanceResponseType isLoadBalanceResponse_LoadBalanceResponseType `protobuf_oneof:"load_balance_response_type"`
-}
-
-func (m *LoadBalanceResponse) Reset()                    { *m = LoadBalanceResponse{} }
-func (m *LoadBalanceResponse) String() string            { return proto.CompactTextString(m) }
-func (*LoadBalanceResponse) ProtoMessage()               {}
-func (*LoadBalanceResponse) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{5} }
-
-type isLoadBalanceResponse_LoadBalanceResponseType interface {
-	isLoadBalanceResponse_LoadBalanceResponseType()
-}
-
-type LoadBalanceResponse_InitialResponse struct {
-	InitialResponse *InitialLoadBalanceResponse `protobuf:"bytes,1,opt,name=initial_response,json=initialResponse,oneof"`
-}
-type LoadBalanceResponse_ServerList struct {
-	ServerList *ServerList `protobuf:"bytes,2,opt,name=server_list,json=serverList,oneof"`
-}
-
-func (*LoadBalanceResponse_InitialResponse) isLoadBalanceResponse_LoadBalanceResponseType() {}
-func (*LoadBalanceResponse_ServerList) isLoadBalanceResponse_LoadBalanceResponseType()      {}
-
-func (m *LoadBalanceResponse) GetLoadBalanceResponseType() isLoadBalanceResponse_LoadBalanceResponseType {
-	if m != nil {
-		return m.LoadBalanceResponseType
-	}
-	return nil
-}
-
-func (m *LoadBalanceResponse) GetInitialResponse() *InitialLoadBalanceResponse {
-	if x, ok := m.GetLoadBalanceResponseType().(*LoadBalanceResponse_InitialResponse); ok {
-		return x.InitialResponse
-	}
-	return nil
-}
-
-func (m *LoadBalanceResponse) GetServerList() *ServerList {
-	if x, ok := m.GetLoadBalanceResponseType().(*LoadBalanceResponse_ServerList); ok {
-		return x.ServerList
-	}
-	return nil
-}
-
-// XXX_OneofFuncs is for the internal use of the proto package.
-func (*LoadBalanceResponse) XXX_OneofFuncs() (func(msg proto.Message, b *proto.Buffer) error, func(msg proto.Message, tag, wire int, b *proto.Buffer) (bool, error), func(msg proto.Message) (n int), []interface{}) {
-	return _LoadBalanceResponse_OneofMarshaler, _LoadBalanceResponse_OneofUnmarshaler, _LoadBalanceResponse_OneofSizer, []interface{}{
-		(*LoadBalanceResponse_InitialResponse)(nil),
-		(*LoadBalanceResponse_ServerList)(nil),
-	}
-}
-
-func _LoadBalanceResponse_OneofMarshaler(msg proto.Message, b *proto.Buffer) error {
-	m := msg.(*LoadBalanceResponse)
-	// load_balance_response_type
-	switch x := m.LoadBalanceResponseType.(type) {
-	case *LoadBalanceResponse_InitialResponse:
-		b.EncodeVarint(1<<3 | proto.WireBytes)
-		if err := b.EncodeMessage(x.InitialResponse); err != nil {
-			return err
-		}
-	case *LoadBalanceResponse_ServerList:
-		b.EncodeVarint(2<<3 | proto.WireBytes)
-		if err := b.EncodeMessage(x.ServerList); err != nil {
-			return err
-		}
-	case nil:
-	default:
-		return fmt.Errorf("LoadBalanceResponse.LoadBalanceResponseType has unexpected type %T", x)
-	}
-	return nil
-}
-
-func _LoadBalanceResponse_OneofUnmarshaler(msg proto.Message, tag, wire int, b *proto.Buffer) (bool, error) {
-	m := msg.(*LoadBalanceResponse)
-	switch tag {
-	case 1: // load_balance_response_type.initial_response
-		if wire != proto.WireBytes {
-			return true, proto.ErrInternalBadWireType
-		}
-		msg := new(InitialLoadBalanceResponse)
-		err := b.DecodeMessage(msg)
-		m.LoadBalanceResponseType = &LoadBalanceResponse_InitialResponse{msg}
-		return true, err
-	case 2: // load_balance_response_type.server_list
-		if wire != proto.WireBytes {
-			return true, proto.ErrInternalBadWireType
-		}
-		msg := new(ServerList)
-		err := b.DecodeMessage(msg)
-		m.LoadBalanceResponseType = &LoadBalanceResponse_ServerList{msg}
-		return true, err
-	default:
-		return false, nil
-	}
-}
-
-func _LoadBalanceResponse_OneofSizer(msg proto.Message) (n int) {
-	m := msg.(*LoadBalanceResponse)
-	// load_balance_response_type
-	switch x := m.LoadBalanceResponseType.(type) {
-	case *LoadBalanceResponse_InitialResponse:
-		s := proto.Size(x.InitialResponse)
-		n += proto.SizeVarint(1<<3 | proto.WireBytes)
-		n += proto.SizeVarint(uint64(s))
-		n += s
-	case *LoadBalanceResponse_ServerList:
-		s := proto.Size(x.ServerList)
-		n += proto.SizeVarint(2<<3 | proto.WireBytes)
-		n += proto.SizeVarint(uint64(s))
-		n += s
-	case nil:
-	default:
-		panic(fmt.Sprintf("proto: unexpected type %T in oneof", x))
-	}
-	return n
-}
-
-type InitialLoadBalanceResponse struct {
-	// This is an application layer redirect that indicates the client should use
-	// the specified server for load balancing. When this field is non-empty in
-	// the response, the client should open a separate connection to the
-	// load_balancer_delegate and call the BalanceLoad method. Its length should
-	// be less than 64 bytes.
-	LoadBalancerDelegate string `protobuf:"bytes,1,opt,name=load_balancer_delegate,json=loadBalancerDelegate" json:"load_balancer_delegate,omitempty"`
-	// This interval defines how often the client should send the client stats
-	// to the load balancer. Stats should only be reported when the duration is
-	// positive.
-	ClientStatsReportInterval *Duration `protobuf:"bytes,2,opt,name=client_stats_report_interval,json=clientStatsReportInterval" json:"client_stats_report_interval,omitempty"`
-}
-
-func (m *InitialLoadBalanceResponse) Reset()                    { *m = InitialLoadBalanceResponse{} }
-func (m *InitialLoadBalanceResponse) String() string            { return proto.CompactTextString(m) }
-func (*InitialLoadBalanceResponse) ProtoMessage()               {}
-func (*InitialLoadBalanceResponse) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{6} }
-
-func (m *InitialLoadBalanceResponse) GetLoadBalancerDelegate() string {
-	if m != nil {
-		return m.LoadBalancerDelegate
-	}
-	return ""
-}
-
-func (m *InitialLoadBalanceResponse) GetClientStatsReportInterval() *Duration {
-	if m != nil {
-		return m.ClientStatsReportInterval
-	}
-	return nil
-}
-
-type ServerList struct {
-	// Contains a list of servers selected by the load balancer. The list will
-	// be updated when server resolutions change or as needed to balance load
-	// across more servers. The client should consume the server list in order
-	// unless instructed otherwise via the client_config.
-	Servers []*Server `protobuf:"bytes,1,rep,name=servers" json:"servers,omitempty"`
-}
-
-func (m *ServerList) Reset()                    { *m = ServerList{} }
-func (m *ServerList) String() string            { return proto.CompactTextString(m) }
-func (*ServerList) ProtoMessage()               {}
-func (*ServerList) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{7} }
-
-func (m *ServerList) GetServers() []*Server {
-	if m != nil {
-		return m.Servers
-	}
-	return nil
-}
-
-// Contains server information. When none of the [drop_for_*] fields are true,
-// use the other fields. When drop_for_rate_limiting is true, ignore all other
-// fields. Use drop_for_load_balancing only when it is true and
-// drop_for_rate_limiting is false.
-type Server struct {
-	// A resolved address for the server, serialized in network-byte-order. It may
-	// either be an IPv4 or IPv6 address.
-	IpAddress []byte `protobuf:"bytes,1,opt,name=ip_address,json=ipAddress,proto3" json:"ip_address,omitempty"`
-	// A resolved port number for the server.
-	Port int32 `protobuf:"varint,2,opt,name=port" json:"port,omitempty"`
-	// An opaque but printable token given to the frontend for each pick. All
-	// frontend requests for that pick must include the token in its initial
-	// metadata. The token is used by the backend to verify the request and to
-	// allow the backend to report load to the gRPC LB system.
-	//
-	// Its length is variable but less than 50 bytes.
-	LoadBalanceToken string `protobuf:"bytes,3,opt,name=load_balance_token,json=loadBalanceToken" json:"load_balance_token,omitempty"`
-	// Indicates whether this particular request should be dropped by the client
-	// for rate limiting.
-	DropForRateLimiting bool `protobuf:"varint,4,opt,name=drop_for_rate_limiting,json=dropForRateLimiting" json:"drop_for_rate_limiting,omitempty"`
-	// Indicates whether this particular request should be dropped by the client
-	// for load balancing.
-	DropForLoadBalancing bool `protobuf:"varint,5,opt,name=drop_for_load_balancing,json=dropForLoadBalancing" json:"drop_for_load_balancing,omitempty"`
-}
-
-func (m *Server) Reset()                    { *m = Server{} }
-func (m *Server) String() string            { return proto.CompactTextString(m) }
-func (*Server) ProtoMessage()               {}
-func (*Server) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{8} }
-
-func (m *Server) GetIpAddress() []byte {
-	if m != nil {
-		return m.IpAddress
-	}
-	return nil
-}
-
-func (m *Server) GetPort() int32 {
-	if m != nil {
-		return m.Port
-	}
-	return 0
-}
-
-func (m *Server) GetLoadBalanceToken() string {
-	if m != nil {
-		return m.LoadBalanceToken
-	}
-	return ""
-}
-
-func (m *Server) GetDropForRateLimiting() bool {
-	if m != nil {
-		return m.DropForRateLimiting
-	}
-	return false
-}
-
-func (m *Server) GetDropForLoadBalancing() bool {
-	if m != nil {
-		return m.DropForLoadBalancing
-	}
-	return false
-}
-
-func init() {
-	proto.RegisterType((*Duration)(nil), "grpc.lb.v1.Duration")
-	proto.RegisterType((*Timestamp)(nil), "grpc.lb.v1.Timestamp")
-	proto.RegisterType((*LoadBalanceRequest)(nil), "grpc.lb.v1.LoadBalanceRequest")
-	proto.RegisterType((*InitialLoadBalanceRequest)(nil), "grpc.lb.v1.InitialLoadBalanceRequest")
-	proto.RegisterType((*ClientStats)(nil), "grpc.lb.v1.ClientStats")
-	proto.RegisterType((*LoadBalanceResponse)(nil), "grpc.lb.v1.LoadBalanceResponse")
-	proto.RegisterType((*InitialLoadBalanceResponse)(nil), "grpc.lb.v1.InitialLoadBalanceResponse")
-	proto.RegisterType((*ServerList)(nil), "grpc.lb.v1.ServerList")
-	proto.RegisterType((*Server)(nil), "grpc.lb.v1.Server")
-}
-
-func init() { proto.RegisterFile("grpc_lb_v1/messages/messages.proto", fileDescriptor0) }
-
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-	// 709 bytes of a gzipped FileDescriptorProto
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-	0x8f, 0x24, 0xbe, 0xc0, 0xd3, 0xdb, 0x24, 0x92, 0x67, 0x70, 0xc6, 0x45, 0x80, 0x3e, 0xb3, 0x8a,
-	0x19, 0x94, 0x7e, 0x63, 0xce, 0x09, 0x6c, 0x4d, 0x13, 0x88, 0x3f, 0xd5, 0x91, 0xc3, 0x9f, 0xaa,
-	0x2e, 0x4a, 0x9f, 0x74, 0xe0, 0xe1, 0x14, 0xfa, 0x0b, 0xa9, 0x2e, 0x25, 0xd3, 0xd8, 0x47, 0x31,
-	0x46, 0xbf, 0x31, 0xef, 0x28, 0x37, 0xae, 0x53, 0xbe, 0x8f, 0x50, 0x34, 0x01, 0x79, 0xbf, 0x0a,
-	0xb0, 0x74, 0xe5, 0xd9, 0x98, 0x50, 0x49, 0x83, 0xa4, 0x0b, 0xb5, 0xcc, 0x01, 0x71, 0x2c, 0x79,
-	0x1a, 0x5b, 0xf7, 0x59, 0x20, 0x46, 0x77, 0x66, 0xe8, 0xe2, 0xc4, 0x03, 0x09, 0xe9, 0x0b, 0xa8,
-	0x1a, 0xd4, 0x63, 0xd4, 0x2c, 0x10, 0xc6, 0x26, 0x1e, 0x58, 0xce, 0xf3, 0x75, 0xdd, 0xf1, 0x89,
-	0x70, 0x1e, 0x02, 0x33, 0xd9, 0xb5, 0xd7, 0x61, 0xed, 0x9a, 0x03, 0x62, 0xce, 0xd8, 0x02, 0x3f,
-	0x0a, 0xb0, 0x76, 0x7b, 0x29, 0xe4, 0x19, 0x2c, 0xe7, 0x93, 0x35, 0xf3, 0x31, 0xc0, 0x01, 0xb7,
-	0xa9, 0x2d, 0xea, 0x41, 0x96, 0xa4, 0x0f, 0x93, 0x33, 0xf2, 0x11, 0xd6, 0xf3, 0x96, 0x65, 0x1a,
-	0x43, 0xa5, 0x2d, 0x13, 0xd2, 0xa2, 0x1e, 0xf3, 0x20, 0x29, 0xbf, 0x9e, 0x2f, 0x3f, 0x1d, 0x62,
-	0x74, 0x35, 0xe7, 0x5e, 0xea, 0xf2, 0x8e, 0x93, 0x34, 0xef, 0x0d, 0x40, 0x76, 0x4b, 0xb2, 0x1d,
-	0x0d, 0xac, 0x68, 0x17, 0x0d, 0xac, 0x62, 0xb3, 0xba, 0x47, 0x6e, 0xb6, 0x83, 0xa6, 0x90, 0x77,
-	0xa5, 0x72, 0xb1, 0x56, 0xf2, 0x7e, 0x17, 0x60, 0x2e, 0x3e, 0x21, 0x1b, 0x00, 0x22, 0x64, 0xdc,
-	0xf7, 0x35, 0x9a, 0x78, 0xe4, 0x2d, 0xd0, 0x8a, 0x08, 0xdf, 0xc6, 0x81, 0xc8, 0xfd, 0x91, 0x76,
-	0x32, 0xf3, 0xdc, 0x3a, 0x32, 0xe3, 0x95, 0x4e, 0x5a, 0x75, 0x81, 0xd2, 0x99, 0xb1, 0x42, 0x6b,
-	0xb9, 0x46, 0x9c, 0x46, 0x71, 0xb2, 0x0f, 0xcb, 0x77, 0x98, 0xae, 0x4c, 0x97, 0xfc, 0x29, 0x06,
-	0x7b, 0x0e, 0x2b, 0x77, 0x19, 0xa9, 0x4c, 0xeb, 0xfe, 0x14, 0xd3, 0xb4, 0xe1, 0x73, 0x39, 0xfd,
-	0x47, 0xf4, 0xe6, 0xdc, 0x4f, 0x62, 0xff, 0x4f, 0x00, 0x00, 0x00, 0xff, 0xff, 0xa3, 0x36, 0x86,
-	0xa6, 0x4a, 0x06, 0x00, 0x00,
-}
diff --git a/vendor/google.golang.org/grpc/grpclb/grpc_lb_v1/messages/messages.proto b/vendor/google.golang.org/grpc/grpclb/grpc_lb_v1/messages/messages.proto
deleted file mode 100644
index 2ed0455..0000000
--- a/vendor/google.golang.org/grpc/grpclb/grpc_lb_v1/messages/messages.proto
+++ /dev/null
@@ -1,155 +0,0 @@
-// Copyright 2016 gRPC authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-syntax = "proto3";
-
-package grpc.lb.v1;
-option go_package = "messages";
-
-message Duration {
-  // Signed seconds of the span of time. Must be from -315,576,000,000
-  // to +315,576,000,000 inclusive.
-  int64 seconds = 1;
-
-  // Signed fractions of a second at nanosecond resolution of the span
-  // of time. Durations less than one second are represented with a 0
-  // `seconds` field and a positive or negative `nanos` field. For durations
-  // of one second or more, a non-zero value for the `nanos` field must be
-  // of the same sign as the `seconds` field. Must be from -999,999,999
-  // to +999,999,999 inclusive.
-  int32 nanos = 2;
-}
-
-message Timestamp {
-  // Represents seconds of UTC time since Unix epoch
-  // 1970-01-01T00:00:00Z. Must be from 0001-01-01T00:00:00Z to
-  // 9999-12-31T23:59:59Z inclusive.
-  int64 seconds = 1;
-
-  // Non-negative fractions of a second at nanosecond resolution. Negative
-  // second values with fractions must still have non-negative nanos values
-  // that count forward in time. Must be from 0 to 999,999,999
-  // inclusive.
-  int32 nanos = 2;
-}
-
-message LoadBalanceRequest {
-  oneof load_balance_request_type {
-    // This message should be sent on the first request to the load balancer.
-    InitialLoadBalanceRequest initial_request = 1;
-
-    // The client stats should be periodically reported to the load balancer
-    // based on the duration defined in the InitialLoadBalanceResponse.
-    ClientStats client_stats = 2;
-  }
-}
-
-message InitialLoadBalanceRequest {
-  // Name of load balanced service (IE, balancer.service.com)
-  // length should be less than 256 bytes.
-  string name = 1;
-}
-
-// Contains client level statistics that are useful to load balancing. Each
-// count except the timestamp should be reset to zero after reporting the stats.
-message ClientStats {
-  // The timestamp of generating the report.
-  Timestamp timestamp = 1;
-
-  // The total number of RPCs that started.
-  int64 num_calls_started = 2;
-
-  // The total number of RPCs that finished.
-  int64 num_calls_finished = 3;
-
-  // The total number of RPCs that were dropped by the client because of rate
-  // limiting.
-  int64 num_calls_finished_with_drop_for_rate_limiting = 4;
-
-  // The total number of RPCs that were dropped by the client because of load
-  // balancing.
-  int64 num_calls_finished_with_drop_for_load_balancing = 5;
-
-  // The total number of RPCs that failed to reach a server except dropped RPCs.
-  int64 num_calls_finished_with_client_failed_to_send = 6;
-
-  // The total number of RPCs that finished and are known to have been received
-  // by a server.
-  int64 num_calls_finished_known_received = 7;
-}
-
-message LoadBalanceResponse {
-  oneof load_balance_response_type {
-    // This message should be sent on the first response to the client.
-    InitialLoadBalanceResponse initial_response = 1;
-
-    // Contains the list of servers selected by the load balancer. The client
-    // should send requests to these servers in the specified order.
-    ServerList server_list = 2;
-  }
-}
-
-message InitialLoadBalanceResponse {
-  // This is an application layer redirect that indicates the client should use
-  // the specified server for load balancing. When this field is non-empty in
-  // the response, the client should open a separate connection to the
-  // load_balancer_delegate and call the BalanceLoad method. Its length should
-  // be less than 64 bytes.
-  string load_balancer_delegate = 1;
-
-  // This interval defines how often the client should send the client stats
-  // to the load balancer. Stats should only be reported when the duration is
-  // positive.
-  Duration client_stats_report_interval = 2;
-}
-
-message ServerList {
-  // Contains a list of servers selected by the load balancer. The list will
-  // be updated when server resolutions change or as needed to balance load
-  // across more servers. The client should consume the server list in order
-  // unless instructed otherwise via the client_config.
-  repeated Server servers = 1;
-
-  // Was google.protobuf.Duration expiration_interval.
-  reserved 3;
-}
-
-// Contains server information. When none of the [drop_for_*] fields are true,
-// use the other fields. When drop_for_rate_limiting is true, ignore all other
-// fields. Use drop_for_load_balancing only when it is true and
-// drop_for_rate_limiting is false.
-message Server {
-  // A resolved address for the server, serialized in network-byte-order. It may
-  // either be an IPv4 or IPv6 address.
-  bytes ip_address = 1;
-
-  // A resolved port number for the server.
-  int32 port = 2;
-
-  // An opaque but printable token given to the frontend for each pick. All
-  // frontend requests for that pick must include the token in its initial
-  // metadata. The token is used by the backend to verify the request and to
-  // allow the backend to report load to the gRPC LB system.
-  //
-  // Its length is variable but less than 50 bytes.
-  string load_balance_token = 3;
-
-  // Indicates whether this particular request should be dropped by the client
-  // for rate limiting.
-  bool drop_for_rate_limiting = 4;
-
-  // Indicates whether this particular request should be dropped by the client
-  // for load balancing.
-  bool drop_for_load_balancing = 5;
-}
diff --git a/vendor/google.golang.org/grpc/grpclog/grpclog.go b/vendor/google.golang.org/grpc/grpclog/grpclog.go
index 16a7d88..1fabb11 100644
--- a/vendor/google.golang.org/grpc/grpclog/grpclog.go
+++ b/vendor/google.golang.org/grpc/grpclog/grpclog.go
@@ -105,18 +105,21 @@ func Fatalln(args ...interface{}) {
 }
 
 // Print prints to the logger. Arguments are handled in the manner of fmt.Print.
+//
 // Deprecated: use Info.
 func Print(args ...interface{}) {
 	logger.Info(args...)
 }
 
 // Printf prints to the logger. Arguments are handled in the manner of fmt.Printf.
+//
 // Deprecated: use Infof.
 func Printf(format string, args ...interface{}) {
 	logger.Infof(format, args...)
 }
 
 // Println prints to the logger. Arguments are handled in the manner of fmt.Println.
+//
 // Deprecated: use Infoln.
 func Println(args ...interface{}) {
 	logger.Infoln(args...)
diff --git a/vendor/google.golang.org/grpc/grpclog/logger.go b/vendor/google.golang.org/grpc/grpclog/logger.go
index d03b239..097494f 100644
--- a/vendor/google.golang.org/grpc/grpclog/logger.go
+++ b/vendor/google.golang.org/grpc/grpclog/logger.go
@@ -19,6 +19,7 @@
 package grpclog
 
 // Logger mimics golang's standard Logger as an interface.
+//
 // Deprecated: use LoggerV2.
 type Logger interface {
 	Fatal(args ...interface{})
@@ -31,6 +32,7 @@ type Logger interface {
 
 // SetLogger sets the logger that is used in grpc. Call only from
 // init() functions.
+//
 // Deprecated: use SetLoggerV2.
 func SetLogger(l Logger) {
 	logger = &loggerWrapper{Logger: l}
diff --git a/vendor/google.golang.org/grpc/interceptor.go b/vendor/google.golang.org/grpc/interceptor.go
index 06dc825..1f6ef67 100644
--- a/vendor/google.golang.org/grpc/interceptor.go
+++ b/vendor/google.golang.org/grpc/interceptor.go
@@ -48,7 +48,9 @@ type UnaryServerInfo struct {
 }
 
 // UnaryHandler defines the handler invoked by UnaryServerInterceptor to complete the normal
-// execution of a unary RPC.
+// execution of a unary RPC. If a UnaryHandler returns an error, it should be produced by the
+// status package, or else gRPC will use codes.Unknown as the status code and err.Error() as
+// the status message of the RPC.
 type UnaryHandler func(ctx context.Context, req interface{}) (interface{}, error)
 
 // UnaryServerInterceptor provides a hook to intercept the execution of a unary RPC on the server. info
diff --git a/vendor/google.golang.org/grpc/internal/backoff/backoff.go b/vendor/google.golang.org/grpc/internal/backoff/backoff.go
new file mode 100644
index 0000000..1bd0cce
--- /dev/null
+++ b/vendor/google.golang.org/grpc/internal/backoff/backoff.go
@@ -0,0 +1,78 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package backoff implement the backoff strategy for gRPC.
+//
+// This is kept in internal until the gRPC project decides whether or not to
+// allow alternative backoff strategies.
+package backoff
+
+import (
+	"time"
+
+	"google.golang.org/grpc/internal/grpcrand"
+)
+
+// Strategy defines the methodology for backing off after a grpc connection
+// failure.
+//
+type Strategy interface {
+	// Backoff returns the amount of time to wait before the next retry given
+	// the number of consecutive failures.
+	Backoff(retries int) time.Duration
+}
+
+const (
+	// baseDelay is the amount of time to wait before retrying after the first
+	// failure.
+	baseDelay = 1.0 * time.Second
+	// factor is applied to the backoff after each retry.
+	factor = 1.6
+	// jitter provides a range to randomize backoff delays.
+	jitter = 0.2
+)
+
+// Exponential implements exponential backoff algorithm as defined in
+// https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md.
+type Exponential struct {
+	// MaxDelay is the upper bound of backoff delay.
+	MaxDelay time.Duration
+}
+
+// Backoff returns the amount of time to wait before the next retry given the
+// number of retries.
+func (bc Exponential) Backoff(retries int) time.Duration {
+	if retries == 0 {
+		return baseDelay
+	}
+	backoff, max := float64(baseDelay), float64(bc.MaxDelay)
+	for backoff < max && retries > 0 {
+		backoff *= factor
+		retries--
+	}
+	if backoff > max {
+		backoff = max
+	}
+	// Randomize backoff delays so that if a cluster of requests start at
+	// the same time, they won't operate in lockstep.
+	backoff *= 1 + jitter*(grpcrand.Float64()*2-1)
+	if backoff < 0 {
+		return 0
+	}
+	return time.Duration(backoff)
+}
diff --git a/vendor/google.golang.org/grpc/internal/channelz/funcs.go b/vendor/google.golang.org/grpc/internal/channelz/funcs.go
new file mode 100644
index 0000000..586a033
--- /dev/null
+++ b/vendor/google.golang.org/grpc/internal/channelz/funcs.go
@@ -0,0 +1,573 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package channelz defines APIs for enabling channelz service, entry
+// registration/deletion, and accessing channelz data. It also defines channelz
+// metric struct formats.
+//
+// All APIs in this package are experimental.
+package channelz
+
+import (
+	"sort"
+	"sync"
+	"sync/atomic"
+
+	"google.golang.org/grpc/grpclog"
+)
+
+var (
+	db    dbWrapper
+	idGen idGenerator
+	// EntryPerPage defines the number of channelz entries to be shown on a web page.
+	EntryPerPage = 50
+	curState     int32
+)
+
+// TurnOn turns on channelz data collection.
+func TurnOn() {
+	if !IsOn() {
+		NewChannelzStorage()
+		atomic.StoreInt32(&curState, 1)
+	}
+}
+
+// IsOn returns whether channelz data collection is on.
+func IsOn() bool {
+	return atomic.CompareAndSwapInt32(&curState, 1, 1)
+}
+
+// dbWarpper wraps around a reference to internal channelz data storage, and
+// provide synchronized functionality to set and get the reference.
+type dbWrapper struct {
+	mu sync.RWMutex
+	DB *channelMap
+}
+
+func (d *dbWrapper) set(db *channelMap) {
+	d.mu.Lock()
+	d.DB = db
+	d.mu.Unlock()
+}
+
+func (d *dbWrapper) get() *channelMap {
+	d.mu.RLock()
+	defer d.mu.RUnlock()
+	return d.DB
+}
+
+// NewChannelzStorage initializes channelz data storage and id generator.
+//
+// Note: This function is exported for testing purpose only. User should not call
+// it in most cases.
+func NewChannelzStorage() {
+	db.set(&channelMap{
+		topLevelChannels: make(map[int64]struct{}),
+		channels:         make(map[int64]*channel),
+		listenSockets:    make(map[int64]*listenSocket),
+		normalSockets:    make(map[int64]*normalSocket),
+		servers:          make(map[int64]*server),
+		subChannels:      make(map[int64]*subChannel),
+	})
+	idGen.reset()
+}
+
+// GetTopChannels returns a slice of top channel's ChannelMetric, along with a
+// boolean indicating whether there's more top channels to be queried for.
+//
+// The arg id specifies that only top channel with id at or above it will be included
+// in the result. The returned slice is up to a length of EntryPerPage, and is
+// sorted in ascending id order.
+func GetTopChannels(id int64) ([]*ChannelMetric, bool) {
+	return db.get().GetTopChannels(id)
+}
+
+// GetServers returns a slice of server's ServerMetric, along with a
+// boolean indicating whether there's more servers to be queried for.
+//
+// The arg id specifies that only server with id at or above it will be included
+// in the result. The returned slice is up to a length of EntryPerPage, and is
+// sorted in ascending id order.
+func GetServers(id int64) ([]*ServerMetric, bool) {
+	return db.get().GetServers(id)
+}
+
+// GetServerSockets returns a slice of server's (identified by id) normal socket's
+// SocketMetric, along with a boolean indicating whether there's more sockets to
+// be queried for.
+//
+// The arg startID specifies that only sockets with id at or above it will be
+// included in the result. The returned slice is up to a length of EntryPerPage,
+// and is sorted in ascending id order.
+func GetServerSockets(id int64, startID int64) ([]*SocketMetric, bool) {
+	return db.get().GetServerSockets(id, startID)
+}
+
+// GetChannel returns the ChannelMetric for the channel (identified by id).
+func GetChannel(id int64) *ChannelMetric {
+	return db.get().GetChannel(id)
+}
+
+// GetSubChannel returns the SubChannelMetric for the subchannel (identified by id).
+func GetSubChannel(id int64) *SubChannelMetric {
+	return db.get().GetSubChannel(id)
+}
+
+// GetSocket returns the SocketInternalMetric for the socket (identified by id).
+func GetSocket(id int64) *SocketMetric {
+	return db.get().GetSocket(id)
+}
+
+// RegisterChannel registers the given channel c in channelz database with ref
+// as its reference name, and add it to the child list of its parent (identified
+// by pid). pid = 0 means no parent. It returns the unique channelz tracking id
+// assigned to this channel.
+func RegisterChannel(c Channel, pid int64, ref string) int64 {
+	id := idGen.genID()
+	cn := &channel{
+		refName:     ref,
+		c:           c,
+		subChans:    make(map[int64]string),
+		nestedChans: make(map[int64]string),
+		id:          id,
+		pid:         pid,
+	}
+	if pid == 0 {
+		db.get().addChannel(id, cn, true, pid, ref)
+	} else {
+		db.get().addChannel(id, cn, false, pid, ref)
+	}
+	return id
+}
+
+// RegisterSubChannel registers the given channel c in channelz database with ref
+// as its reference name, and add it to the child list of its parent (identified
+// by pid). It returns the unique channelz tracking id assigned to this subchannel.
+func RegisterSubChannel(c Channel, pid int64, ref string) int64 {
+	if pid == 0 {
+		grpclog.Error("a SubChannel's parent id cannot be 0")
+		return 0
+	}
+	id := idGen.genID()
+	sc := &subChannel{
+		refName: ref,
+		c:       c,
+		sockets: make(map[int64]string),
+		id:      id,
+		pid:     pid,
+	}
+	db.get().addSubChannel(id, sc, pid, ref)
+	return id
+}
+
+// RegisterServer registers the given server s in channelz database. It returns
+// the unique channelz tracking id assigned to this server.
+func RegisterServer(s Server, ref string) int64 {
+	id := idGen.genID()
+	svr := &server{
+		refName:       ref,
+		s:             s,
+		sockets:       make(map[int64]string),
+		listenSockets: make(map[int64]string),
+		id:            id,
+	}
+	db.get().addServer(id, svr)
+	return id
+}
+
+// RegisterListenSocket registers the given listen socket s in channelz database
+// with ref as its reference name, and add it to the child list of its parent
+// (identified by pid). It returns the unique channelz tracking id assigned to
+// this listen socket.
+func RegisterListenSocket(s Socket, pid int64, ref string) int64 {
+	if pid == 0 {
+		grpclog.Error("a ListenSocket's parent id cannot be 0")
+		return 0
+	}
+	id := idGen.genID()
+	ls := &listenSocket{refName: ref, s: s, id: id, pid: pid}
+	db.get().addListenSocket(id, ls, pid, ref)
+	return id
+}
+
+// RegisterNormalSocket registers the given normal socket s in channelz database
+// with ref as its reference name, and add it to the child list of its parent
+// (identified by pid). It returns the unique channelz tracking id assigned to
+// this normal socket.
+func RegisterNormalSocket(s Socket, pid int64, ref string) int64 {
+	if pid == 0 {
+		grpclog.Error("a NormalSocket's parent id cannot be 0")
+		return 0
+	}
+	id := idGen.genID()
+	ns := &normalSocket{refName: ref, s: s, id: id, pid: pid}
+	db.get().addNormalSocket(id, ns, pid, ref)
+	return id
+}
+
+// RemoveEntry removes an entry with unique channelz trakcing id to be id from
+// channelz database.
+func RemoveEntry(id int64) {
+	db.get().removeEntry(id)
+}
+
+// channelMap is the storage data structure for channelz.
+// Methods of channelMap can be divided in two two categories with respect to locking.
+// 1. Methods acquire the global lock.
+// 2. Methods that can only be called when global lock is held.
+// A second type of method need always to be called inside a first type of method.
+type channelMap struct {
+	mu               sync.RWMutex
+	topLevelChannels map[int64]struct{}
+	servers          map[int64]*server
+	channels         map[int64]*channel
+	subChannels      map[int64]*subChannel
+	listenSockets    map[int64]*listenSocket
+	normalSockets    map[int64]*normalSocket
+}
+
+func (c *channelMap) addServer(id int64, s *server) {
+	c.mu.Lock()
+	s.cm = c
+	c.servers[id] = s
+	c.mu.Unlock()
+}
+
+func (c *channelMap) addChannel(id int64, cn *channel, isTopChannel bool, pid int64, ref string) {
+	c.mu.Lock()
+	cn.cm = c
+	c.channels[id] = cn
+	if isTopChannel {
+		c.topLevelChannels[id] = struct{}{}
+	} else {
+		c.findEntry(pid).addChild(id, cn)
+	}
+	c.mu.Unlock()
+}
+
+func (c *channelMap) addSubChannel(id int64, sc *subChannel, pid int64, ref string) {
+	c.mu.Lock()
+	sc.cm = c
+	c.subChannels[id] = sc
+	c.findEntry(pid).addChild(id, sc)
+	c.mu.Unlock()
+}
+
+func (c *channelMap) addListenSocket(id int64, ls *listenSocket, pid int64, ref string) {
+	c.mu.Lock()
+	ls.cm = c
+	c.listenSockets[id] = ls
+	c.findEntry(pid).addChild(id, ls)
+	c.mu.Unlock()
+}
+
+func (c *channelMap) addNormalSocket(id int64, ns *normalSocket, pid int64, ref string) {
+	c.mu.Lock()
+	ns.cm = c
+	c.normalSockets[id] = ns
+	c.findEntry(pid).addChild(id, ns)
+	c.mu.Unlock()
+}
+
+// removeEntry triggers the removal of an entry, which may not indeed delete the
+// entry, if it has to wait on the deletion of its children, or may lead to a chain
+// of entry deletion. For example, deleting the last socket of a gracefully shutting
+// down server will lead to the server being also deleted.
+func (c *channelMap) removeEntry(id int64) {
+	c.mu.Lock()
+	c.findEntry(id).triggerDelete()
+	c.mu.Unlock()
+}
+
+// c.mu must be held by the caller.
+func (c *channelMap) findEntry(id int64) entry {
+	var v entry
+	var ok bool
+	if v, ok = c.channels[id]; ok {
+		return v
+	}
+	if v, ok = c.subChannels[id]; ok {
+		return v
+	}
+	if v, ok = c.servers[id]; ok {
+		return v
+	}
+	if v, ok = c.listenSockets[id]; ok {
+		return v
+	}
+	if v, ok = c.normalSockets[id]; ok {
+		return v
+	}
+	return &dummyEntry{idNotFound: id}
+}
+
+// c.mu must be held by the caller
+// deleteEntry simply deletes an entry from the channelMap. Before calling this
+// method, caller must check this entry is ready to be deleted, i.e removeEntry()
+// has been called on it, and no children still exist.
+// Conditionals are ordered by the expected frequency of deletion of each entity
+// type, in order to optimize performance.
+func (c *channelMap) deleteEntry(id int64) {
+	var ok bool
+	if _, ok = c.normalSockets[id]; ok {
+		delete(c.normalSockets, id)
+		return
+	}
+	if _, ok = c.subChannels[id]; ok {
+		delete(c.subChannels, id)
+		return
+	}
+	if _, ok = c.channels[id]; ok {
+		delete(c.channels, id)
+		delete(c.topLevelChannels, id)
+		return
+	}
+	if _, ok = c.listenSockets[id]; ok {
+		delete(c.listenSockets, id)
+		return
+	}
+	if _, ok = c.servers[id]; ok {
+		delete(c.servers, id)
+		return
+	}
+}
+
+type int64Slice []int64
+
+func (s int64Slice) Len() int           { return len(s) }
+func (s int64Slice) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s int64Slice) Less(i, j int) bool { return s[i] < s[j] }
+
+func copyMap(m map[int64]string) map[int64]string {
+	n := make(map[int64]string)
+	for k, v := range m {
+		n[k] = v
+	}
+	return n
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func (c *channelMap) GetTopChannels(id int64) ([]*ChannelMetric, bool) {
+	c.mu.RLock()
+	l := len(c.topLevelChannels)
+	ids := make([]int64, 0, l)
+	cns := make([]*channel, 0, min(l, EntryPerPage))
+
+	for k := range c.topLevelChannels {
+		ids = append(ids, k)
+	}
+	sort.Sort(int64Slice(ids))
+	idx := sort.Search(len(ids), func(i int) bool { return ids[i] >= id })
+	count := 0
+	var end bool
+	var t []*ChannelMetric
+	for i, v := range ids[idx:] {
+		if count == EntryPerPage {
+			break
+		}
+		if cn, ok := c.channels[v]; ok {
+			cns = append(cns, cn)
+			t = append(t, &ChannelMetric{
+				NestedChans: copyMap(cn.nestedChans),
+				SubChans:    copyMap(cn.subChans),
+			})
+			count++
+		}
+		if i == len(ids[idx:])-1 {
+			end = true
+			break
+		}
+	}
+	c.mu.RUnlock()
+	if count == 0 {
+		end = true
+	}
+
+	for i, cn := range cns {
+		t[i].ChannelData = cn.c.ChannelzMetric()
+		t[i].ID = cn.id
+		t[i].RefName = cn.refName
+	}
+	return t, end
+}
+
+func (c *channelMap) GetServers(id int64) ([]*ServerMetric, bool) {
+	c.mu.RLock()
+	l := len(c.servers)
+	ids := make([]int64, 0, l)
+	ss := make([]*server, 0, min(l, EntryPerPage))
+	for k := range c.servers {
+		ids = append(ids, k)
+	}
+	sort.Sort(int64Slice(ids))
+	idx := sort.Search(len(ids), func(i int) bool { return ids[i] >= id })
+	count := 0
+	var end bool
+	var s []*ServerMetric
+	for i, v := range ids[idx:] {
+		if count == EntryPerPage {
+			break
+		}
+		if svr, ok := c.servers[v]; ok {
+			ss = append(ss, svr)
+			s = append(s, &ServerMetric{
+				ListenSockets: copyMap(svr.listenSockets),
+			})
+			count++
+		}
+		if i == len(ids[idx:])-1 {
+			end = true
+			break
+		}
+	}
+	c.mu.RUnlock()
+	if count == 0 {
+		end = true
+	}
+
+	for i, svr := range ss {
+		s[i].ServerData = svr.s.ChannelzMetric()
+		s[i].ID = svr.id
+		s[i].RefName = svr.refName
+	}
+	return s, end
+}
+
+func (c *channelMap) GetServerSockets(id int64, startID int64) ([]*SocketMetric, bool) {
+	var svr *server
+	var ok bool
+	c.mu.RLock()
+	if svr, ok = c.servers[id]; !ok {
+		// server with id doesn't exist.
+		c.mu.RUnlock()
+		return nil, true
+	}
+	svrskts := svr.sockets
+	l := len(svrskts)
+	ids := make([]int64, 0, l)
+	sks := make([]*normalSocket, 0, min(l, EntryPerPage))
+	for k := range svrskts {
+		ids = append(ids, k)
+	}
+	sort.Sort((int64Slice(ids)))
+	idx := sort.Search(len(ids), func(i int) bool { return ids[i] >= id })
+	count := 0
+	var end bool
+	for i, v := range ids[idx:] {
+		if count == EntryPerPage {
+			break
+		}
+		if ns, ok := c.normalSockets[v]; ok {
+			sks = append(sks, ns)
+			count++
+		}
+		if i == len(ids[idx:])-1 {
+			end = true
+			break
+		}
+	}
+	c.mu.RUnlock()
+	if count == 0 {
+		end = true
+	}
+	var s []*SocketMetric
+	for _, ns := range sks {
+		sm := &SocketMetric{}
+		sm.SocketData = ns.s.ChannelzMetric()
+		sm.ID = ns.id
+		sm.RefName = ns.refName
+		s = append(s, sm)
+	}
+	return s, end
+}
+
+func (c *channelMap) GetChannel(id int64) *ChannelMetric {
+	cm := &ChannelMetric{}
+	var cn *channel
+	var ok bool
+	c.mu.RLock()
+	if cn, ok = c.channels[id]; !ok {
+		// channel with id doesn't exist.
+		c.mu.RUnlock()
+		return nil
+	}
+	cm.NestedChans = copyMap(cn.nestedChans)
+	cm.SubChans = copyMap(cn.subChans)
+	c.mu.RUnlock()
+	cm.ChannelData = cn.c.ChannelzMetric()
+	cm.ID = cn.id
+	cm.RefName = cn.refName
+	return cm
+}
+
+func (c *channelMap) GetSubChannel(id int64) *SubChannelMetric {
+	cm := &SubChannelMetric{}
+	var sc *subChannel
+	var ok bool
+	c.mu.RLock()
+	if sc, ok = c.subChannels[id]; !ok {
+		// subchannel with id doesn't exist.
+		c.mu.RUnlock()
+		return nil
+	}
+	cm.Sockets = copyMap(sc.sockets)
+	c.mu.RUnlock()
+	cm.ChannelData = sc.c.ChannelzMetric()
+	cm.ID = sc.id
+	cm.RefName = sc.refName
+	return cm
+}
+
+func (c *channelMap) GetSocket(id int64) *SocketMetric {
+	sm := &SocketMetric{}
+	c.mu.RLock()
+	if ls, ok := c.listenSockets[id]; ok {
+		c.mu.RUnlock()
+		sm.SocketData = ls.s.ChannelzMetric()
+		sm.ID = ls.id
+		sm.RefName = ls.refName
+		return sm
+	}
+	if ns, ok := c.normalSockets[id]; ok {
+		c.mu.RUnlock()
+		sm.SocketData = ns.s.ChannelzMetric()
+		sm.ID = ns.id
+		sm.RefName = ns.refName
+		return sm
+	}
+	c.mu.RUnlock()
+	return nil
+}
+
+type idGenerator struct {
+	id int64
+}
+
+func (i *idGenerator) reset() {
+	atomic.StoreInt64(&i.id, 0)
+}
+
+func (i *idGenerator) genID() int64 {
+	return atomic.AddInt64(&i.id, 1)
+}
diff --git a/vendor/google.golang.org/grpc/internal/channelz/types.go b/vendor/google.golang.org/grpc/internal/channelz/types.go
new file mode 100644
index 0000000..153d753
--- /dev/null
+++ b/vendor/google.golang.org/grpc/internal/channelz/types.go
@@ -0,0 +1,418 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package channelz
+
+import (
+	"net"
+	"time"
+
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/grpclog"
+)
+
+// entry represents a node in the channelz database.
+type entry interface {
+	// addChild adds a child e, whose channelz id is id to child list
+	addChild(id int64, e entry)
+	// deleteChild deletes a child with channelz id to be id from child list
+	deleteChild(id int64)
+	// triggerDelete tries to delete self from channelz database. However, if child
+	// list is not empty, then deletion from the database is on hold until the last
+	// child is deleted from database.
+	triggerDelete()
+	// deleteSelfIfReady check whether triggerDelete() has been called before, and whether child
+	// list is now empty. If both conditions are met, then delete self from database.
+	deleteSelfIfReady()
+}
+
+// dummyEntry is a fake entry to handle entry not found case.
+type dummyEntry struct {
+	idNotFound int64
+}
+
+func (d *dummyEntry) addChild(id int64, e entry) {
+	// Note: It is possible for a normal program to reach here under race condition.
+	// For example, there could be a race between ClientConn.Close() info being propagated
+	// to addrConn and http2Client. ClientConn.Close() cancel the context and result
+	// in http2Client to error. The error info is then caught by transport monitor
+	// and before addrConn.tearDown() is called in side ClientConn.Close(). Therefore,
+	// the addrConn will create a new transport. And when registering the new transport in
+	// channelz, its parent addrConn could have already been torn down and deleted
+	// from channelz tracking, and thus reach the code here.
+	grpclog.Infof("attempt to add child of type %T with id %d to a parent (id=%d) that doesn't currently exist", e, id, d.idNotFound)
+}
+
+func (d *dummyEntry) deleteChild(id int64) {
+	// It is possible for a normal program to reach here under race condition.
+	// Refer to the example described in addChild().
+	grpclog.Infof("attempt to delete child with id %d from a parent (id=%d) that doesn't currently exist", id, d.idNotFound)
+}
+
+func (d *dummyEntry) triggerDelete() {
+	grpclog.Warningf("attempt to delete an entry (id=%d) that doesn't currently exist", d.idNotFound)
+}
+
+func (*dummyEntry) deleteSelfIfReady() {
+	// code should not reach here. deleteSelfIfReady is always called on an existing entry.
+}
+
+// ChannelMetric defines the info channelz provides for a specific Channel, which
+// includes ChannelInternalMetric and channelz-specific data, such as channelz id,
+// child list, etc.
+type ChannelMetric struct {
+	// ID is the channelz id of this channel.
+	ID int64
+	// RefName is the human readable reference string of this channel.
+	RefName string
+	// ChannelData contains channel internal metric reported by the channel through
+	// ChannelzMetric().
+	ChannelData *ChannelInternalMetric
+	// NestedChans tracks the nested channel type children of this channel in the format of
+	// a map from nested channel channelz id to corresponding reference string.
+	NestedChans map[int64]string
+	// SubChans tracks the subchannel type children of this channel in the format of a
+	// map from subchannel channelz id to corresponding reference string.
+	SubChans map[int64]string
+	// Sockets tracks the socket type children of this channel in the format of a map
+	// from socket channelz id to corresponding reference string.
+	// Note current grpc implementation doesn't allow channel having sockets directly,
+	// therefore, this is field is unused.
+	Sockets map[int64]string
+}
+
+// SubChannelMetric defines the info channelz provides for a specific SubChannel,
+// which includes ChannelInternalMetric and channelz-specific data, such as
+// channelz id, child list, etc.
+type SubChannelMetric struct {
+	// ID is the channelz id of this subchannel.
+	ID int64
+	// RefName is the human readable reference string of this subchannel.
+	RefName string
+	// ChannelData contains subchannel internal metric reported by the subchannel
+	// through ChannelzMetric().
+	ChannelData *ChannelInternalMetric
+	// NestedChans tracks the nested channel type children of this subchannel in the format of
+	// a map from nested channel channelz id to corresponding reference string.
+	// Note current grpc implementation doesn't allow subchannel to have nested channels
+	// as children, therefore, this field is unused.
+	NestedChans map[int64]string
+	// SubChans tracks the subchannel type children of this subchannel in the format of a
+	// map from subchannel channelz id to corresponding reference string.
+	// Note current grpc implementation doesn't allow subchannel to have subchannels
+	// as children, therefore, this field is unused.
+	SubChans map[int64]string
+	// Sockets tracks the socket type children of this subchannel in the format of a map
+	// from socket channelz id to corresponding reference string.
+	Sockets map[int64]string
+}
+
+// ChannelInternalMetric defines the struct that the implementor of Channel interface
+// should return from ChannelzMetric().
+type ChannelInternalMetric struct {
+	// current connectivity state of the channel.
+	State connectivity.State
+	// The target this channel originally tried to connect to.  May be absent
+	Target string
+	// The number of calls started on the channel.
+	CallsStarted int64
+	// The number of calls that have completed with an OK status.
+	CallsSucceeded int64
+	// The number of calls that have a completed with a non-OK status.
+	CallsFailed int64
+	// The last time a call was started on the channel.
+	LastCallStartedTimestamp time.Time
+	//TODO: trace
+}
+
+// Channel is the interface that should be satisfied in order to be tracked by
+// channelz as Channel or SubChannel.
+type Channel interface {
+	ChannelzMetric() *ChannelInternalMetric
+}
+
+type channel struct {
+	refName     string
+	c           Channel
+	closeCalled bool
+	nestedChans map[int64]string
+	subChans    map[int64]string
+	id          int64
+	pid         int64
+	cm          *channelMap
+}
+
+func (c *channel) addChild(id int64, e entry) {
+	switch v := e.(type) {
+	case *subChannel:
+		c.subChans[id] = v.refName
+	case *channel:
+		c.nestedChans[id] = v.refName
+	default:
+		grpclog.Errorf("cannot add a child (id = %d) of type %T to a channel", id, e)
+	}
+}
+
+func (c *channel) deleteChild(id int64) {
+	delete(c.subChans, id)
+	delete(c.nestedChans, id)
+	c.deleteSelfIfReady()
+}
+
+func (c *channel) triggerDelete() {
+	c.closeCalled = true
+	c.deleteSelfIfReady()
+}
+
+func (c *channel) deleteSelfIfReady() {
+	if !c.closeCalled || len(c.subChans)+len(c.nestedChans) != 0 {
+		return
+	}
+	c.cm.deleteEntry(c.id)
+	// not top channel
+	if c.pid != 0 {
+		c.cm.findEntry(c.pid).deleteChild(c.id)
+	}
+}
+
+type subChannel struct {
+	refName     string
+	c           Channel
+	closeCalled bool
+	sockets     map[int64]string
+	id          int64
+	pid         int64
+	cm          *channelMap
+}
+
+func (sc *subChannel) addChild(id int64, e entry) {
+	if v, ok := e.(*normalSocket); ok {
+		sc.sockets[id] = v.refName
+	} else {
+		grpclog.Errorf("cannot add a child (id = %d) of type %T to a subChannel", id, e)
+	}
+}
+
+func (sc *subChannel) deleteChild(id int64) {
+	delete(sc.sockets, id)
+	sc.deleteSelfIfReady()
+}
+
+func (sc *subChannel) triggerDelete() {
+	sc.closeCalled = true
+	sc.deleteSelfIfReady()
+}
+
+func (sc *subChannel) deleteSelfIfReady() {
+	if !sc.closeCalled || len(sc.sockets) != 0 {
+		return
+	}
+	sc.cm.deleteEntry(sc.id)
+	sc.cm.findEntry(sc.pid).deleteChild(sc.id)
+}
+
+// SocketMetric defines the info channelz provides for a specific Socket, which
+// includes SocketInternalMetric and channelz-specific data, such as channelz id, etc.
+type SocketMetric struct {
+	// ID is the channelz id of this socket.
+	ID int64
+	// RefName is the human readable reference string of this socket.
+	RefName string
+	// SocketData contains socket internal metric reported by the socket through
+	// ChannelzMetric().
+	SocketData *SocketInternalMetric
+}
+
+// SocketInternalMetric defines the struct that the implementor of Socket interface
+// should return from ChannelzMetric().
+type SocketInternalMetric struct {
+	// The number of streams that have been started.
+	StreamsStarted int64
+	// The number of streams that have ended successfully:
+	// On client side, receiving frame with eos bit set.
+	// On server side, sending frame with eos bit set.
+	StreamsSucceeded int64
+	// The number of streams that have ended unsuccessfully:
+	// On client side, termination without receiving frame with eos bit set.
+	// On server side, termination without sending frame with eos bit set.
+	StreamsFailed int64
+	// The number of messages successfully sent on this socket.
+	MessagesSent     int64
+	MessagesReceived int64
+	// The number of keep alives sent.  This is typically implemented with HTTP/2
+	// ping messages.
+	KeepAlivesSent int64
+	// The last time a stream was created by this endpoint.  Usually unset for
+	// servers.
+	LastLocalStreamCreatedTimestamp time.Time
+	// The last time a stream was created by the remote endpoint.  Usually unset
+	// for clients.
+	LastRemoteStreamCreatedTimestamp time.Time
+	// The last time a message was sent by this endpoint.
+	LastMessageSentTimestamp time.Time
+	// The last time a message was received by this endpoint.
+	LastMessageReceivedTimestamp time.Time
+	// The amount of window, granted to the local endpoint by the remote endpoint.
+	// This may be slightly out of date due to network latency.  This does NOT
+	// include stream level or TCP level flow control info.
+	LocalFlowControlWindow int64
+	// The amount of window, granted to the remote endpoint by the local endpoint.
+	// This may be slightly out of date due to network latency.  This does NOT
+	// include stream level or TCP level flow control info.
+	RemoteFlowControlWindow int64
+	// The locally bound address.
+	LocalAddr net.Addr
+	// The remote bound address.  May be absent.
+	RemoteAddr net.Addr
+	// Optional, represents the name of the remote endpoint, if different than
+	// the original target name.
+	RemoteName string
+	//TODO: socket options
+	//TODO: Security
+}
+
+// Socket is the interface that should be satisfied in order to be tracked by
+// channelz as Socket.
+type Socket interface {
+	ChannelzMetric() *SocketInternalMetric
+}
+
+type listenSocket struct {
+	refName string
+	s       Socket
+	id      int64
+	pid     int64
+	cm      *channelMap
+}
+
+func (ls *listenSocket) addChild(id int64, e entry) {
+	grpclog.Errorf("cannot add a child (id = %d) of type %T to a listen socket", id, e)
+}
+
+func (ls *listenSocket) deleteChild(id int64) {
+	grpclog.Errorf("cannot delete a child (id = %d) from a listen socket", id)
+}
+
+func (ls *listenSocket) triggerDelete() {
+	ls.cm.deleteEntry(ls.id)
+	ls.cm.findEntry(ls.pid).deleteChild(ls.id)
+}
+
+func (ls *listenSocket) deleteSelfIfReady() {
+	grpclog.Errorf("cannot call deleteSelfIfReady on a listen socket")
+}
+
+type normalSocket struct {
+	refName string
+	s       Socket
+	id      int64
+	pid     int64
+	cm      *channelMap
+}
+
+func (ns *normalSocket) addChild(id int64, e entry) {
+	grpclog.Errorf("cannot add a child (id = %d) of type %T to a normal socket", id, e)
+}
+
+func (ns *normalSocket) deleteChild(id int64) {
+	grpclog.Errorf("cannot delete a child (id = %d) from a normal socket", id)
+}
+
+func (ns *normalSocket) triggerDelete() {
+	ns.cm.deleteEntry(ns.id)
+	ns.cm.findEntry(ns.pid).deleteChild(ns.id)
+}
+
+func (ns *normalSocket) deleteSelfIfReady() {
+	grpclog.Errorf("cannot call deleteSelfIfReady on a normal socket")
+}
+
+// ServerMetric defines the info channelz provides for a specific Server, which
+// includes ServerInternalMetric and channelz-specific data, such as channelz id,
+// child list, etc.
+type ServerMetric struct {
+	// ID is the channelz id of this server.
+	ID int64
+	// RefName is the human readable reference string of this server.
+	RefName string
+	// ServerData contains server internal metric reported by the server through
+	// ChannelzMetric().
+	ServerData *ServerInternalMetric
+	// ListenSockets tracks the listener socket type children of this server in the
+	// format of a map from socket channelz id to corresponding reference string.
+	ListenSockets map[int64]string
+}
+
+// ServerInternalMetric defines the struct that the implementor of Server interface
+// should return from ChannelzMetric().
+type ServerInternalMetric struct {
+	// The number of incoming calls started on the server.
+	CallsStarted int64
+	// The number of incoming calls that have completed with an OK status.
+	CallsSucceeded int64
+	// The number of incoming calls that have a completed with a non-OK status.
+	CallsFailed int64
+	// The last time a call was started on the server.
+	LastCallStartedTimestamp time.Time
+	//TODO: trace
+}
+
+// Server is the interface to be satisfied in order to be tracked by channelz as
+// Server.
+type Server interface {
+	ChannelzMetric() *ServerInternalMetric
+}
+
+type server struct {
+	refName       string
+	s             Server
+	closeCalled   bool
+	sockets       map[int64]string
+	listenSockets map[int64]string
+	id            int64
+	cm            *channelMap
+}
+
+func (s *server) addChild(id int64, e entry) {
+	switch v := e.(type) {
+	case *normalSocket:
+		s.sockets[id] = v.refName
+	case *listenSocket:
+		s.listenSockets[id] = v.refName
+	default:
+		grpclog.Errorf("cannot add a child (id = %d) of type %T to a server", id, e)
+	}
+}
+
+func (s *server) deleteChild(id int64) {
+	delete(s.sockets, id)
+	delete(s.listenSockets, id)
+	s.deleteSelfIfReady()
+}
+
+func (s *server) triggerDelete() {
+	s.closeCalled = true
+	s.deleteSelfIfReady()
+}
+
+func (s *server) deleteSelfIfReady() {
+	if !s.closeCalled || len(s.sockets)+len(s.listenSockets) != 0 {
+		return
+	}
+	s.cm.deleteEntry(s.id)
+}
diff --git a/vendor/google.golang.org/grpc/internal/grpcrand/grpcrand.go b/vendor/google.golang.org/grpc/internal/grpcrand/grpcrand.go
new file mode 100644
index 0000000..200b115
--- /dev/null
+++ b/vendor/google.golang.org/grpc/internal/grpcrand/grpcrand.go
@@ -0,0 +1,56 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package grpcrand implements math/rand functions in a concurrent-safe way
+// with a global random source, independent of math/rand's global source.
+package grpcrand
+
+import (
+	"math/rand"
+	"sync"
+	"time"
+)
+
+var (
+	r  = rand.New(rand.NewSource(time.Now().UnixNano()))
+	mu sync.Mutex
+)
+
+// Int63n implements rand.Int63n on the grpcrand global source.
+func Int63n(n int64) int64 {
+	mu.Lock()
+	res := r.Int63n(n)
+	mu.Unlock()
+	return res
+}
+
+// Intn implements rand.Intn on the grpcrand global source.
+func Intn(n int) int {
+	mu.Lock()
+	res := r.Intn(n)
+	mu.Unlock()
+	return res
+}
+
+// Float64 implements rand.Float64 on the grpcrand global source.
+func Float64() float64 {
+	mu.Lock()
+	res := r.Float64()
+	mu.Unlock()
+	return res
+}
diff --git a/vendor/google.golang.org/grpc/internal/internal.go b/vendor/google.golang.org/grpc/internal/internal.go
index 0708383..cd34267 100644
--- a/vendor/google.golang.org/grpc/internal/internal.go
+++ b/vendor/google.golang.org/grpc/internal/internal.go
@@ -15,20 +15,22 @@
  *
  */
 
-// Package internal contains gRPC-internal code for testing, to avoid polluting
-// the godoc of the top-level grpc package.
+// Package internal contains gRPC-internal code, to avoid polluting
+// the godoc of the top-level grpc package.  It must not import any grpc
+// symbols to avoid circular dependencies.
 package internal
 
-// TestingCloseConns closes all existing transports but keeps
-// grpcServer.lis accepting new connections.
-//
-// The provided grpcServer must be of type *grpc.Server. It is untyped
-// for circular dependency reasons.
-var TestingCloseConns func(grpcServer interface{})
+var (
 
-// TestingUseHandlerImpl enables the http.Handler-based server implementation.
-// It must be called before Serve and requires TLS credentials.
-//
-// The provided grpcServer must be of type *grpc.Server. It is untyped
-// for circular dependency reasons.
-var TestingUseHandlerImpl func(grpcServer interface{})
+	// TestingUseHandlerImpl enables the http.Handler-based server implementation.
+	// It must be called before Serve and requires TLS credentials.
+	//
+	// The provided grpcServer must be of type *grpc.Server. It is untyped
+	// for circular dependency reasons.
+	TestingUseHandlerImpl func(grpcServer interface{})
+
+	// WithContextDialer is exported by clientconn.go
+	WithContextDialer interface{} // func(context.Context, string) (net.Conn, error) grpc.DialOption
+	// WithResolverBuilder is exported by clientconn.go
+	WithResolverBuilder interface{} // func (resolver.Builder) grpc.DialOption
+)
diff --git a/vendor/google.golang.org/grpc/metadata/metadata.go b/vendor/google.golang.org/grpc/metadata/metadata.go
index ccfea5d..bd2eaf4 100644
--- a/vendor/google.golang.org/grpc/metadata/metadata.go
+++ b/vendor/google.golang.org/grpc/metadata/metadata.go
@@ -17,7 +17,8 @@
  */
 
 // Package metadata define the structure of the metadata supported by gRPC library.
-// Please refer to https://grpc.io/docs/guides/wire.html for more information about custom-metadata.
+// Please refer to https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md
+// for more information about custom-metadata.
 package metadata // import "google.golang.org/grpc/metadata"
 
 import (
@@ -27,7 +28,9 @@ import (
 	"golang.org/x/net/context"
 )
 
-// DecodeKeyValue returns k, v, nil.  It is deprecated and should not be used.
+// DecodeKeyValue returns k, v, nil.
+//
+// Deprecated: use k and v directly instead.
 func DecodeKeyValue(k, v string) (string, string, error) {
 	return k, v, nil
 }
@@ -94,6 +97,30 @@ func (md MD) Copy() MD {
 	return Join(md)
 }
 
+// Get obtains the values for a given key.
+func (md MD) Get(k string) []string {
+	k = strings.ToLower(k)
+	return md[k]
+}
+
+// Set sets the value of a given key with a slice of values.
+func (md MD) Set(k string, vals ...string) {
+	if len(vals) == 0 {
+		return
+	}
+	k = strings.ToLower(k)
+	md[k] = vals
+}
+
+// Append adds the values to key k, not overwriting what was already stored at that key.
+func (md MD) Append(k string, vals ...string) {
+	if len(vals) == 0 {
+		return
+	}
+	k = strings.ToLower(k)
+	md[k] = append(md[k], vals...)
+}
+
 // Join joins any number of mds into a single MD.
 // The order of values for each key is determined by the order in which
 // the mds containing those values are presented to Join.
@@ -115,9 +142,26 @@ func NewIncomingContext(ctx context.Context, md MD) context.Context {
 	return context.WithValue(ctx, mdIncomingKey{}, md)
 }
 
-// NewOutgoingContext creates a new context with outgoing md attached.
+// NewOutgoingContext creates a new context with outgoing md attached. If used
+// in conjunction with AppendToOutgoingContext, NewOutgoingContext will
+// overwrite any previously-appended metadata.
 func NewOutgoingContext(ctx context.Context, md MD) context.Context {
-	return context.WithValue(ctx, mdOutgoingKey{}, md)
+	return context.WithValue(ctx, mdOutgoingKey{}, rawMD{md: md})
+}
+
+// AppendToOutgoingContext returns a new context with the provided kv merged
+// with any existing metadata in the context. Please refer to the
+// documentation of Pairs for a description of kv.
+func AppendToOutgoingContext(ctx context.Context, kv ...string) context.Context {
+	if len(kv)%2 == 1 {
+		panic(fmt.Sprintf("metadata: AppendToOutgoingContext got an odd number of input pairs for metadata: %d", len(kv)))
+	}
+	md, _ := ctx.Value(mdOutgoingKey{}).(rawMD)
+	added := make([][]string, len(md.added)+1)
+	copy(added, md.added)
+	added[len(added)-1] = make([]string, len(kv))
+	copy(added[len(added)-1], kv)
+	return context.WithValue(ctx, mdOutgoingKey{}, rawMD{md: md.md, added: added})
 }
 
 // FromIncomingContext returns the incoming metadata in ctx if it exists.  The
@@ -128,10 +172,39 @@ func FromIncomingContext(ctx context.Context) (md MD, ok bool) {
 	return
 }
 
+// FromOutgoingContextRaw returns the un-merged, intermediary contents
+// of rawMD. Remember to perform strings.ToLower on the keys. The returned
+// MD should not be modified. Writing to it may cause races. Modification
+// should be made to copies of the returned MD.
+//
+// This is intended for gRPC-internal use ONLY.
+func FromOutgoingContextRaw(ctx context.Context) (MD, [][]string, bool) {
+	raw, ok := ctx.Value(mdOutgoingKey{}).(rawMD)
+	if !ok {
+		return nil, nil, false
+	}
+
+	return raw.md, raw.added, true
+}
+
 // FromOutgoingContext returns the outgoing metadata in ctx if it exists.  The
 // returned MD should not be modified. Writing to it may cause races.
-// Modification should be made to the copies of the returned MD.
-func FromOutgoingContext(ctx context.Context) (md MD, ok bool) {
-	md, ok = ctx.Value(mdOutgoingKey{}).(MD)
-	return
+// Modification should be made to copies of the returned MD.
+func FromOutgoingContext(ctx context.Context) (MD, bool) {
+	raw, ok := ctx.Value(mdOutgoingKey{}).(rawMD)
+	if !ok {
+		return nil, false
+	}
+
+	mds := make([]MD, 0, len(raw.added)+1)
+	mds = append(mds, raw.md)
+	for _, vv := range raw.added {
+		mds = append(mds, Pairs(vv...))
+	}
+	return Join(mds...), ok
+}
+
+type rawMD struct {
+	md    MD
+	added [][]string
 }
diff --git a/vendor/google.golang.org/grpc/naming/dns_resolver.go b/vendor/google.golang.org/grpc/naming/dns_resolver.go
index 7e69a2c..0f8a908 100644
--- a/vendor/google.golang.org/grpc/naming/dns_resolver.go
+++ b/vendor/google.golang.org/grpc/naming/dns_resolver.go
@@ -153,10 +153,10 @@ type ipWatcher struct {
 	updateChan chan *Update
 }
 
-// Next returns the adrress resolution Update for the target. For IP address,
-// the resolution is itself, thus polling name server is unncessary. Therefore,
+// Next returns the address resolution Update for the target. For IP address,
+// the resolution is itself, thus polling name server is unnecessary. Therefore,
 // Next() will return an Update the first time it is called, and will be blocked
-// for all following calls as no Update exisits until watcher is closed.
+// for all following calls as no Update exists until watcher is closed.
 func (i *ipWatcher) Next() ([]*Update, error) {
 	u, ok := <-i.updateChan
 	if !ok {
diff --git a/vendor/google.golang.org/grpc/naming/go17.go b/vendor/google.golang.org/grpc/naming/go17.go
index 8bdf21e..57b65d7 100644
--- a/vendor/google.golang.org/grpc/naming/go17.go
+++ b/vendor/google.golang.org/grpc/naming/go17.go
@@ -1,4 +1,4 @@
-// +build go1.7, !go1.8
+// +build go1.6,!go1.8
 
 /*
  *
diff --git a/vendor/google.golang.org/grpc/naming/naming.go b/vendor/google.golang.org/grpc/naming/naming.go
index 1af7e32..8cc39e9 100644
--- a/vendor/google.golang.org/grpc/naming/naming.go
+++ b/vendor/google.golang.org/grpc/naming/naming.go
@@ -18,20 +18,26 @@
 
 // Package naming defines the naming API and related data structures for gRPC.
 // The interface is EXPERIMENTAL and may be suject to change.
+//
+// Deprecated: please use package resolver.
 package naming
 
 // Operation defines the corresponding operations for a name resolution change.
+//
+// Deprecated: please use package resolver.
 type Operation uint8
 
 const (
 	// Add indicates a new address is added.
 	Add Operation = iota
-	// Delete indicates an exisiting address is deleted.
+	// Delete indicates an existing address is deleted.
 	Delete
 )
 
 // Update defines a name resolution update. Notice that it is not valid having both
 // empty string Addr and nil Metadata in an Update.
+//
+// Deprecated: please use package resolver.
 type Update struct {
 	// Op indicates the operation of the update.
 	Op Operation
@@ -43,12 +49,16 @@ type Update struct {
 }
 
 // Resolver creates a Watcher for a target to track its resolution changes.
+//
+// Deprecated: please use package resolver.
 type Resolver interface {
 	// Resolve creates a Watcher for target.
 	Resolve(target string) (Watcher, error)
 }
 
 // Watcher watches for the updates on the specified target.
+//
+// Deprecated: please use package resolver.
 type Watcher interface {
 	// Next blocks until an update or error happens. It may return one or more
 	// updates. The first call should get the full set of the results. It should
diff --git a/vendor/google.golang.org/grpc/picker_wrapper.go b/vendor/google.golang.org/grpc/picker_wrapper.go
index 9085dbc..019e658 100644
--- a/vendor/google.golang.org/grpc/picker_wrapper.go
+++ b/vendor/google.golang.org/grpc/picker_wrapper.go
@@ -19,12 +19,17 @@
 package grpc
 
 import (
+	"io"
 	"sync"
+	"sync/atomic"
 
 	"golang.org/x/net/context"
 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/internal/channelz"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/resolver"
 	"google.golang.org/grpc/status"
 	"google.golang.org/grpc/transport"
 )
@@ -36,13 +41,57 @@ type pickerWrapper struct {
 	done       bool
 	blockingCh chan struct{}
 	picker     balancer.Picker
+
+	// The latest connection happened.
+	connErrMu sync.Mutex
+	connErr   error
+
+	stickinessMDKey atomic.Value
+	stickiness      *stickyStore
 }
 
 func newPickerWrapper() *pickerWrapper {
-	bp := &pickerWrapper{blockingCh: make(chan struct{})}
+	bp := &pickerWrapper{
+		blockingCh: make(chan struct{}),
+		stickiness: newStickyStore(),
+	}
 	return bp
 }
 
+func (bp *pickerWrapper) updateConnectionError(err error) {
+	bp.connErrMu.Lock()
+	bp.connErr = err
+	bp.connErrMu.Unlock()
+}
+
+func (bp *pickerWrapper) connectionError() error {
+	bp.connErrMu.Lock()
+	err := bp.connErr
+	bp.connErrMu.Unlock()
+	return err
+}
+
+func (bp *pickerWrapper) updateStickinessMDKey(newKey string) {
+	// No need to check ok because mdKey == "" if ok == false.
+	if oldKey, _ := bp.stickinessMDKey.Load().(string); oldKey != newKey {
+		bp.stickinessMDKey.Store(newKey)
+		bp.stickiness.reset(newKey)
+	}
+}
+
+func (bp *pickerWrapper) getStickinessMDKey() string {
+	// No need to check ok because mdKey == "" if ok == false.
+	mdKey, _ := bp.stickinessMDKey.Load().(string)
+	return mdKey
+}
+
+func (bp *pickerWrapper) clearStickinessState() {
+	if oldKey := bp.getStickinessMDKey(); oldKey != "" {
+		// There's no need to reset store if mdKey was "".
+		bp.stickiness.reset(oldKey)
+	}
+}
+
 // updatePicker is called by UpdateBalancerState. It unblocks all blocked pick.
 func (bp *pickerWrapper) updatePicker(p balancer.Picker) {
 	bp.mu.Lock()
@@ -57,6 +106,23 @@ func (bp *pickerWrapper) updatePicker(p balancer.Picker) {
 	bp.mu.Unlock()
 }
 
+func doneChannelzWrapper(acw *acBalancerWrapper, done func(balancer.DoneInfo)) func(balancer.DoneInfo) {
+	acw.mu.Lock()
+	ac := acw.ac
+	acw.mu.Unlock()
+	ac.incrCallsStarted()
+	return func(b balancer.DoneInfo) {
+		if b.Err != nil && b.Err != io.EOF {
+			ac.incrCallsFailed()
+		} else {
+			ac.incrCallsSucceeded()
+		}
+		if done != nil {
+			done(b)
+		}
+	}
+}
+
 // pick returns the transport that will be used for the RPC.
 // It may block in the following cases:
 // - there's no picker
@@ -65,6 +131,27 @@ func (bp *pickerWrapper) updatePicker(p balancer.Picker) {
 // - the subConn returned by the current picker is not READY
 // When one of these situations happens, pick blocks until the picker gets updated.
 func (bp *pickerWrapper) pick(ctx context.Context, failfast bool, opts balancer.PickOptions) (transport.ClientTransport, func(balancer.DoneInfo), error) {
+
+	mdKey := bp.getStickinessMDKey()
+	stickyKey, isSticky := stickyKeyFromContext(ctx, mdKey)
+
+	// Potential race here: if stickinessMDKey is updated after the above two
+	// lines, and this pick is a sticky pick, the following put could add an
+	// entry to sticky store with an outdated sticky key.
+	//
+	// The solution: keep the current md key in sticky store, and at the
+	// beginning of each get/put, check the mdkey against store.curMDKey.
+	//  - Cons: one more string comparing for each get/put.
+	//  - Pros: the string matching happens inside get/put, so the overhead for
+	//  non-sticky RPCs will be minimal.
+
+	if isSticky {
+		if t, ok := bp.stickiness.get(mdKey, stickyKey); ok {
+			// Done function returned is always nil.
+			return t, nil, nil
+		}
+	}
+
 	var (
 		p  balancer.Picker
 		ch chan struct{}
@@ -97,7 +184,7 @@ func (bp *pickerWrapper) pick(ctx context.Context, failfast bool, opts balancer.
 		p = bp.picker
 		bp.mu.Unlock()
 
-		subConn, put, err := p.Pick(ctx, opts)
+		subConn, done, err := p.Pick(ctx, opts)
 
 		if err != nil {
 			switch err {
@@ -107,7 +194,7 @@ func (bp *pickerWrapper) pick(ctx context.Context, failfast bool, opts balancer.
 				if !failfast {
 					continue
 				}
-				return nil, nil, status.Errorf(codes.Unavailable, "%v", err)
+				return nil, nil, status.Errorf(codes.Unavailable, "%v, latest connection error: %v", err, bp.connectionError())
 			default:
 				// err is some other error.
 				return nil, nil, toRPCErr(err)
@@ -120,7 +207,13 @@ func (bp *pickerWrapper) pick(ctx context.Context, failfast bool, opts balancer.
 			continue
 		}
 		if t, ok := acw.getAddrConn().getReadyTransport(); ok {
-			return t, put, nil
+			if isSticky {
+				bp.stickiness.put(mdKey, stickyKey, acw)
+			}
+			if channelz.IsOn() {
+				return t, doneChannelzWrapper(acw, done), nil
+			}
+			return t, done, nil
 		}
 		grpclog.Infof("blockingPicker: the picked transport is not ready, loop back to repick")
 		// If ok == false, ac.state is not READY.
@@ -139,3 +232,105 @@ func (bp *pickerWrapper) close() {
 	bp.done = true
 	close(bp.blockingCh)
 }
+
+const stickinessKeyCountLimit = 1000
+
+type stickyStoreEntry struct {
+	acw  *acBalancerWrapper
+	addr resolver.Address
+}
+
+type stickyStore struct {
+	mu sync.Mutex
+	// curMDKey is check before every get/put to avoid races. The operation will
+	// abort immediately when the given mdKey is different from the curMDKey.
+	curMDKey string
+	store    *linkedMap
+}
+
+func newStickyStore() *stickyStore {
+	return &stickyStore{
+		store: newLinkedMap(),
+	}
+}
+
+// reset clears the map in stickyStore, and set the currentMDKey to newMDKey.
+func (ss *stickyStore) reset(newMDKey string) {
+	ss.mu.Lock()
+	ss.curMDKey = newMDKey
+	ss.store.clear()
+	ss.mu.Unlock()
+}
+
+// stickyKey is the key to look up in store. mdKey will be checked against
+// curMDKey to avoid races.
+func (ss *stickyStore) put(mdKey, stickyKey string, acw *acBalancerWrapper) {
+	ss.mu.Lock()
+	defer ss.mu.Unlock()
+	if mdKey != ss.curMDKey {
+		return
+	}
+	// TODO(stickiness): limit the total number of entries.
+	ss.store.put(stickyKey, &stickyStoreEntry{
+		acw:  acw,
+		addr: acw.getAddrConn().getCurAddr(),
+	})
+	if ss.store.len() > stickinessKeyCountLimit {
+		ss.store.removeOldest()
+	}
+}
+
+// stickyKey is the key to look up in store. mdKey will be checked against
+// curMDKey to avoid races.
+func (ss *stickyStore) get(mdKey, stickyKey string) (transport.ClientTransport, bool) {
+	ss.mu.Lock()
+	defer ss.mu.Unlock()
+	if mdKey != ss.curMDKey {
+		return nil, false
+	}
+	entry, ok := ss.store.get(stickyKey)
+	if !ok {
+		return nil, false
+	}
+	ac := entry.acw.getAddrConn()
+	if ac.getCurAddr() != entry.addr {
+		ss.store.remove(stickyKey)
+		return nil, false
+	}
+	t, ok := ac.getReadyTransport()
+	if !ok {
+		ss.store.remove(stickyKey)
+		return nil, false
+	}
+	return t, true
+}
+
+// Get one value from metadata in ctx with key stickinessMDKey.
+//
+// It returns "", false if stickinessMDKey is an empty string.
+func stickyKeyFromContext(ctx context.Context, stickinessMDKey string) (string, bool) {
+	if stickinessMDKey == "" {
+		return "", false
+	}
+
+	md, added, ok := metadata.FromOutgoingContextRaw(ctx)
+	if !ok {
+		return "", false
+	}
+
+	if vv, ok := md[stickinessMDKey]; ok {
+		if len(vv) > 0 {
+			return vv[0], true
+		}
+	}
+
+	for _, ss := range added {
+		for i := 0; i < len(ss)-1; i += 2 {
+			if ss[i] == stickinessMDKey {
+				return ss[i+1], true
+			}
+		}
+	}
+
+	return "", false
+}
diff --git a/vendor/google.golang.org/grpc/pickfirst.go b/vendor/google.golang.org/grpc/pickfirst.go
index 7f993ef..bf659d4 100644
--- a/vendor/google.golang.org/grpc/pickfirst.go
+++ b/vendor/google.golang.org/grpc/pickfirst.go
@@ -26,6 +26,9 @@ import (
 	"google.golang.org/grpc/resolver"
 )
 
+// PickFirstBalancerName is the name of the pick_first balancer.
+const PickFirstBalancerName = "pick_first"
+
 func newPickfirstBuilder() balancer.Builder {
 	return &pickfirstBuilder{}
 }
@@ -37,7 +40,7 @@ func (*pickfirstBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions
 }
 
 func (*pickfirstBuilder) Name() string {
-	return "pickfirst"
+	return PickFirstBalancerName
 }
 
 type pickfirstBalancer struct {
@@ -57,14 +60,20 @@ func (b *pickfirstBalancer) HandleResolvedAddrs(addrs []resolver.Address, err er
 			return
 		}
 		b.cc.UpdateBalancerState(connectivity.Idle, &picker{sc: b.sc})
+		b.sc.Connect()
 	} else {
 		b.sc.UpdateAddresses(addrs)
+		b.sc.Connect()
 	}
 }
 
 func (b *pickfirstBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
 	grpclog.Infof("pickfirstBalancer: HandleSubConnStateChange: %p, %v", sc, s)
-	if b.sc != sc || s == connectivity.Shutdown {
+	if b.sc != sc {
+		grpclog.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
+		return
+	}
+	if s == connectivity.Shutdown {
 		b.sc = nil
 		return
 	}
@@ -93,3 +102,7 @@ func (p *picker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.
 	}
 	return p.sc, nil, nil
 }
+
+func init() {
+	balancer.Register(newPickfirstBuilder())
+}
diff --git a/vendor/google.golang.org/grpc/proxy.go b/vendor/google.golang.org/grpc/proxy.go
index 3e17efe..2d40236 100644
--- a/vendor/google.golang.org/grpc/proxy.go
+++ b/vendor/google.golang.org/grpc/proxy.go
@@ -82,8 +82,7 @@ func doHTTPConnectHandshake(ctx context.Context, conn net.Conn, addr string) (_
 		Header: map[string][]string{"User-Agent": {grpcUA}},
 	})
 
-	req = req.WithContext(ctx)
-	if err := req.Write(conn); err != nil {
+	if err := sendHTTPRequest(ctx, req, conn); err != nil {
 		return nil, fmt.Errorf("failed to write the HTTP request: %v", err)
 	}
 
diff --git a/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go b/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
new file mode 100644
index 0000000..048fde6
--- /dev/null
+++ b/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
@@ -0,0 +1,381 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package dns implements a dns resolver to be installed as the default resolver
+// in grpc.
+package dns
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/internal/grpcrand"
+	"google.golang.org/grpc/resolver"
+)
+
+func init() {
+	resolver.Register(NewBuilder())
+}
+
+const (
+	defaultPort = "443"
+	defaultFreq = time.Minute * 30
+	golang      = "GO"
+	// In DNS, service config is encoded in a TXT record via the mechanism
+	// described in RFC-1464 using the attribute name grpc_config.
+	txtAttribute = "grpc_config="
+)
+
+var (
+	errMissingAddr = errors.New("missing address")
+)
+
+// NewBuilder creates a dnsBuilder which is used to factory DNS resolvers.
+func NewBuilder() resolver.Builder {
+	return &dnsBuilder{freq: defaultFreq}
+}
+
+type dnsBuilder struct {
+	// frequency of polling the DNS server.
+	freq time.Duration
+}
+
+// Build creates and starts a DNS resolver that watches the name resolution of the target.
+func (b *dnsBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
+	if target.Authority != "" {
+		return nil, fmt.Errorf("Default DNS resolver does not support custom DNS server")
+	}
+	host, port, err := parseTarget(target.Endpoint)
+	if err != nil {
+		return nil, err
+	}
+
+	// IP address.
+	if net.ParseIP(host) != nil {
+		host, _ = formatIP(host)
+		addr := []resolver.Address{{Addr: host + ":" + port}}
+		i := &ipResolver{
+			cc: cc,
+			ip: addr,
+			rn: make(chan struct{}, 1),
+			q:  make(chan struct{}),
+		}
+		cc.NewAddress(addr)
+		go i.watcher()
+		return i, nil
+	}
+
+	// DNS address (non-IP).
+	ctx, cancel := context.WithCancel(context.Background())
+	d := &dnsResolver{
+		freq:                 b.freq,
+		host:                 host,
+		port:                 port,
+		ctx:                  ctx,
+		cancel:               cancel,
+		cc:                   cc,
+		t:                    time.NewTimer(0),
+		rn:                   make(chan struct{}, 1),
+		disableServiceConfig: opts.DisableServiceConfig,
+	}
+
+	d.wg.Add(1)
+	go d.watcher()
+	return d, nil
+}
+
+// Scheme returns the naming scheme of this resolver builder, which is "dns".
+func (b *dnsBuilder) Scheme() string {
+	return "dns"
+}
+
+// ipResolver watches for the name resolution update for an IP address.
+type ipResolver struct {
+	cc resolver.ClientConn
+	ip []resolver.Address
+	// rn channel is used by ResolveNow() to force an immediate resolution of the target.
+	rn chan struct{}
+	q  chan struct{}
+}
+
+// ResolveNow resend the address it stores, no resolution is needed.
+func (i *ipResolver) ResolveNow(opt resolver.ResolveNowOption) {
+	select {
+	case i.rn <- struct{}{}:
+	default:
+	}
+}
+
+// Close closes the ipResolver.
+func (i *ipResolver) Close() {
+	close(i.q)
+}
+
+func (i *ipResolver) watcher() {
+	for {
+		select {
+		case <-i.rn:
+			i.cc.NewAddress(i.ip)
+		case <-i.q:
+			return
+		}
+	}
+}
+
+// dnsResolver watches for the name resolution update for a non-IP target.
+type dnsResolver struct {
+	freq   time.Duration
+	host   string
+	port   string
+	ctx    context.Context
+	cancel context.CancelFunc
+	cc     resolver.ClientConn
+	// rn channel is used by ResolveNow() to force an immediate resolution of the target.
+	rn chan struct{}
+	t  *time.Timer
+	// wg is used to enforce Close() to return after the watcher() goroutine has finished.
+	// Otherwise, data race will be possible. [Race Example] in dns_resolver_test we
+	// replace the real lookup functions with mocked ones to facilitate testing.
+	// If Close() doesn't wait for watcher() goroutine finishes, race detector sometimes
+	// will warns lookup (READ the lookup function pointers) inside watcher() goroutine
+	// has data race with replaceNetFunc (WRITE the lookup function pointers).
+	wg                   sync.WaitGroup
+	disableServiceConfig bool
+}
+
+// ResolveNow invoke an immediate resolution of the target that this dnsResolver watches.
+func (d *dnsResolver) ResolveNow(opt resolver.ResolveNowOption) {
+	select {
+	case d.rn <- struct{}{}:
+	default:
+	}
+}
+
+// Close closes the dnsResolver.
+func (d *dnsResolver) Close() {
+	d.cancel()
+	d.wg.Wait()
+	d.t.Stop()
+}
+
+func (d *dnsResolver) watcher() {
+	defer d.wg.Done()
+	for {
+		select {
+		case <-d.ctx.Done():
+			return
+		case <-d.t.C:
+		case <-d.rn:
+		}
+		result, sc := d.lookup()
+		// Next lookup should happen after an interval defined by d.freq.
+		d.t.Reset(d.freq)
+		d.cc.NewServiceConfig(sc)
+		d.cc.NewAddress(result)
+	}
+}
+
+func (d *dnsResolver) lookupSRV() []resolver.Address {
+	var newAddrs []resolver.Address
+	_, srvs, err := lookupSRV(d.ctx, "grpclb", "tcp", d.host)
+	if err != nil {
+		grpclog.Infof("grpc: failed dns SRV record lookup due to %v.\n", err)
+		return nil
+	}
+	for _, s := range srvs {
+		lbAddrs, err := lookupHost(d.ctx, s.Target)
+		if err != nil {
+			grpclog.Infof("grpc: failed load balancer address dns lookup due to %v.\n", err)
+			continue
+		}
+		for _, a := range lbAddrs {
+			a, ok := formatIP(a)
+			if !ok {
+				grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
+				continue
+			}
+			addr := a + ":" + strconv.Itoa(int(s.Port))
+			newAddrs = append(newAddrs, resolver.Address{Addr: addr, Type: resolver.GRPCLB, ServerName: s.Target})
+		}
+	}
+	return newAddrs
+}
+
+func (d *dnsResolver) lookupTXT() string {
+	ss, err := lookupTXT(d.ctx, d.host)
+	if err != nil {
+		grpclog.Infof("grpc: failed dns TXT record lookup due to %v.\n", err)
+		return ""
+	}
+	var res string
+	for _, s := range ss {
+		res += s
+	}
+
+	// TXT record must have "grpc_config=" attribute in order to be used as service config.
+	if !strings.HasPrefix(res, txtAttribute) {
+		grpclog.Warningf("grpc: TXT record %v missing %v attribute", res, txtAttribute)
+		return ""
+	}
+	return strings.TrimPrefix(res, txtAttribute)
+}
+
+func (d *dnsResolver) lookupHost() []resolver.Address {
+	var newAddrs []resolver.Address
+	addrs, err := lookupHost(d.ctx, d.host)
+	if err != nil {
+		grpclog.Warningf("grpc: failed dns A record lookup due to %v.\n", err)
+		return nil
+	}
+	for _, a := range addrs {
+		a, ok := formatIP(a)
+		if !ok {
+			grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
+			continue
+		}
+		addr := a + ":" + d.port
+		newAddrs = append(newAddrs, resolver.Address{Addr: addr})
+	}
+	return newAddrs
+}
+
+func (d *dnsResolver) lookup() ([]resolver.Address, string) {
+	newAddrs := d.lookupSRV()
+	// Support fallback to non-balancer address.
+	newAddrs = append(newAddrs, d.lookupHost()...)
+	if d.disableServiceConfig {
+		return newAddrs, ""
+	}
+	sc := d.lookupTXT()
+	return newAddrs, canaryingSC(sc)
+}
+
+// formatIP returns ok = false if addr is not a valid textual representation of an IP address.
+// If addr is an IPv4 address, return the addr and ok = true.
+// If addr is an IPv6 address, return the addr enclosed in square brackets and ok = true.
+func formatIP(addr string) (addrIP string, ok bool) {
+	ip := net.ParseIP(addr)
+	if ip == nil {
+		return "", false
+	}
+	if ip.To4() != nil {
+		return addr, true
+	}
+	return "[" + addr + "]", true
+}
+
+// parseTarget takes the user input target string, returns formatted host and port info.
+// If target doesn't specify a port, set the port to be the defaultPort.
+// If target is in IPv6 format and host-name is enclosed in sqarue brackets, brackets
+// are strippd when setting the host.
+// examples:
+// target: "www.google.com" returns host: "www.google.com", port: "443"
+// target: "ipv4-host:80" returns host: "ipv4-host", port: "80"
+// target: "[ipv6-host]" returns host: "ipv6-host", port: "443"
+// target: ":80" returns host: "localhost", port: "80"
+// target: ":" returns host: "localhost", port: "443"
+func parseTarget(target string) (host, port string, err error) {
+	if target == "" {
+		return "", "", errMissingAddr
+	}
+	if ip := net.ParseIP(target); ip != nil {
+		// target is an IPv4 or IPv6(without brackets) address
+		return target, defaultPort, nil
+	}
+	if host, port, err = net.SplitHostPort(target); err == nil {
+		// target has port, i.e ipv4-host:port, [ipv6-host]:port, host-name:port
+		if host == "" {
+			// Keep consistent with net.Dial(): If the host is empty, as in ":80", the local system is assumed.
+			host = "localhost"
+		}
+		if port == "" {
+			// If the port field is empty(target ends with colon), e.g. "[::1]:", defaultPort is used.
+			port = defaultPort
+		}
+		return host, port, nil
+	}
+	if host, port, err = net.SplitHostPort(target + ":" + defaultPort); err == nil {
+		// target doesn't have port
+		return host, port, nil
+	}
+	return "", "", fmt.Errorf("invalid target address %v, error info: %v", target, err)
+}
+
+type rawChoice struct {
+	ClientLanguage *[]string        `json:"clientLanguage,omitempty"`
+	Percentage     *int             `json:"percentage,omitempty"`
+	ClientHostName *[]string        `json:"clientHostName,omitempty"`
+	ServiceConfig  *json.RawMessage `json:"serviceConfig,omitempty"`
+}
+
+func containsString(a *[]string, b string) bool {
+	if a == nil {
+		return true
+	}
+	for _, c := range *a {
+		if c == b {
+			return true
+		}
+	}
+	return false
+}
+
+func chosenByPercentage(a *int) bool {
+	if a == nil {
+		return true
+	}
+	return grpcrand.Intn(100)+1 <= *a
+}
+
+func canaryingSC(js string) string {
+	if js == "" {
+		return ""
+	}
+	var rcs []rawChoice
+	err := json.Unmarshal([]byte(js), &rcs)
+	if err != nil {
+		grpclog.Warningf("grpc: failed to parse service config json string due to %v.\n", err)
+		return ""
+	}
+	cliHostname, err := os.Hostname()
+	if err != nil {
+		grpclog.Warningf("grpc: failed to get client hostname due to %v.\n", err)
+		return ""
+	}
+	var sc string
+	for _, c := range rcs {
+		if !containsString(c.ClientLanguage, golang) ||
+			!chosenByPercentage(c.Percentage) ||
+			!containsString(c.ClientHostName, cliHostname) ||
+			c.ServiceConfig == nil {
+			continue
+		}
+		sc = string(*c.ServiceConfig)
+		break
+	}
+	return sc
+}
diff --git a/vendor/google.golang.org/grpc/resolver/dns/go17.go b/vendor/google.golang.org/grpc/resolver/dns/go17.go
new file mode 100644
index 0000000..b466bc8
--- /dev/null
+++ b/vendor/google.golang.org/grpc/resolver/dns/go17.go
@@ -0,0 +1,35 @@
+// +build go1.6, !go1.8
+
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package dns
+
+import (
+	"net"
+
+	"golang.org/x/net/context"
+)
+
+var (
+	lookupHost = func(ctx context.Context, host string) ([]string, error) { return net.LookupHost(host) }
+	lookupSRV  = func(ctx context.Context, service, proto, name string) (string, []*net.SRV, error) {
+		return net.LookupSRV(service, proto, name)
+	}
+	lookupTXT = func(ctx context.Context, name string) ([]string, error) { return net.LookupTXT(name) }
+)
diff --git a/vendor/google.golang.org/grpc/resolver/dns/go18.go b/vendor/google.golang.org/grpc/resolver/dns/go18.go
new file mode 100644
index 0000000..fa34f14
--- /dev/null
+++ b/vendor/google.golang.org/grpc/resolver/dns/go18.go
@@ -0,0 +1,29 @@
+// +build go1.8
+
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package dns
+
+import "net"
+
+var (
+	lookupHost = net.DefaultResolver.LookupHost
+	lookupSRV  = net.DefaultResolver.LookupSRV
+	lookupTXT  = net.DefaultResolver.LookupTXT
+)
diff --git a/vendor/google.golang.org/grpc/resolver/passthrough/passthrough.go b/vendor/google.golang.org/grpc/resolver/passthrough/passthrough.go
new file mode 100644
index 0000000..b76010d
--- /dev/null
+++ b/vendor/google.golang.org/grpc/resolver/passthrough/passthrough.go
@@ -0,0 +1,57 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package passthrough implements a pass-through resolver. It sends the target
+// name without scheme back to gRPC as resolved address.
+package passthrough
+
+import "google.golang.org/grpc/resolver"
+
+const scheme = "passthrough"
+
+type passthroughBuilder struct{}
+
+func (*passthroughBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
+	r := &passthroughResolver{
+		target: target,
+		cc:     cc,
+	}
+	r.start()
+	return r, nil
+}
+
+func (*passthroughBuilder) Scheme() string {
+	return scheme
+}
+
+type passthroughResolver struct {
+	target resolver.Target
+	cc     resolver.ClientConn
+}
+
+func (r *passthroughResolver) start() {
+	r.cc.NewAddress([]resolver.Address{{Addr: r.target.Endpoint}})
+}
+
+func (*passthroughResolver) ResolveNow(o resolver.ResolveNowOption) {}
+
+func (*passthroughResolver) Close() {}
+
+func init() {
+	resolver.Register(&passthroughBuilder{})
+}
diff --git a/vendor/google.golang.org/grpc/resolver/resolver.go b/vendor/google.golang.org/grpc/resolver/resolver.go
index 49307e8..506afac 100644
--- a/vendor/google.golang.org/grpc/resolver/resolver.go
+++ b/vendor/google.golang.org/grpc/resolver/resolver.go
@@ -24,42 +24,42 @@ var (
 	// m is a map from scheme to resolver builder.
 	m = make(map[string]Builder)
 	// defaultScheme is the default scheme to use.
-	defaultScheme string
+	defaultScheme = "passthrough"
 )
 
 // TODO(bar) install dns resolver in init(){}.
 
-// Register registers the resolver builder to the resolver map.
-// b.Scheme will be used as the scheme registered with this builder.
+// Register registers the resolver builder to the resolver map. b.Scheme will be
+// used as the scheme registered with this builder.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. If multiple Resolvers are
+// registered with the same name, the one registered last will take effect.
 func Register(b Builder) {
 	m[b.Scheme()] = b
 }
 
 // Get returns the resolver builder registered with the given scheme.
-// If no builder is register with the scheme, the default scheme will
-// be used.
-// If the default scheme is not modified, "dns" will be the default
-// scheme, and the preinstalled dns resolver will be used.
-// If the default scheme is modified, and a resolver is registered with
-// the scheme, that resolver will be returned.
-// If the default scheme is modified, and no resolver is registered with
-// the scheme, nil will be returned.
+//
+// If no builder is register with the scheme, nil will be returned.
 func Get(scheme string) Builder {
 	if b, ok := m[scheme]; ok {
 		return b
 	}
-	if b, ok := m[defaultScheme]; ok {
-		return b
-	}
 	return nil
 }
 
 // SetDefaultScheme sets the default scheme that will be used.
-// The default default scheme is "dns".
+// The default default scheme is "passthrough".
 func SetDefaultScheme(scheme string) {
 	defaultScheme = scheme
 }
 
+// GetDefaultScheme gets the default scheme that will be used.
+func GetDefaultScheme() string {
+	return defaultScheme
+}
+
 // AddressType indicates the address type returned by name resolution.
 type AddressType uint8
 
@@ -78,7 +78,9 @@ type Address struct {
 	// Type is the type of this address.
 	Type AddressType
 	// ServerName is the name of this address.
-	// It's the name of the grpc load balancer, which will be used for authentication.
+	//
+	// e.g. if Type is GRPCLB, ServerName should be the name of the remote load
+	// balancer, not the name of the backend.
 	ServerName string
 	// Metadata is the information associated with Addr, which may be used
 	// to make load balancing decision.
@@ -88,10 +90,17 @@ type Address struct {
 // BuildOption includes additional information for the builder to create
 // the resolver.
 type BuildOption struct {
+	// DisableServiceConfig indicates whether resolver should fetch service config data.
+	DisableServiceConfig bool
 }
 
 // ClientConn contains the callbacks for resolver to notify any updates
 // to the gRPC ClientConn.
+//
+// This interface is to be implemented by gRPC. Users should not need a
+// brand new implementation of this interface. For the situations like
+// testing, the new implementation should embed this interface. This allows
+// gRPC to add new methods to this interface.
 type ClientConn interface {
 	// NewAddress is called by resolver to notify ClientConn a new list
 	// of resolved addresses.
@@ -128,8 +137,10 @@ type ResolveNowOption struct{}
 // Resolver watches for the updates on the specified target.
 // Updates include address updates and service config updates.
 type Resolver interface {
-	// ResolveNow will be called by gRPC to try to resolve the target name again.
-	// It's just a hint, resolver can ignore this if it's not necessary.
+	// ResolveNow will be called by gRPC to try to resolve the target name
+	// again. It's just a hint, resolver can ignore this if it's not necessary.
+	//
+	// It could be called multiple times concurrently.
 	ResolveNow(ResolveNowOption)
 	// Close closes the resolver.
 	Close()
diff --git a/vendor/google.golang.org/grpc/resolver_conn_wrapper.go b/vendor/google.golang.org/grpc/resolver_conn_wrapper.go
index 7d53964..494d693 100644
--- a/vendor/google.golang.org/grpc/resolver_conn_wrapper.go
+++ b/vendor/google.golang.org/grpc/resolver_conn_wrapper.go
@@ -19,6 +19,7 @@
 package grpc
 
 import (
+	"fmt"
 	"strings"
 
 	"google.golang.org/grpc/grpclog"
@@ -36,39 +37,43 @@ type ccResolverWrapper struct {
 }
 
 // split2 returns the values from strings.SplitN(s, sep, 2).
-// If sep is not found, it returns "", s instead.
-func split2(s, sep string) (string, string) {
+// If sep is not found, it returns ("", s, false) instead.
+func split2(s, sep string) (string, string, bool) {
 	spl := strings.SplitN(s, sep, 2)
 	if len(spl) < 2 {
-		return "", s
+		return "", "", false
 	}
-	return spl[0], spl[1]
+	return spl[0], spl[1], true
 }
 
 // parseTarget splits target into a struct containing scheme, authority and
 // endpoint.
+//
+// If target is not a valid scheme://authority/endpoint, it returns {Endpoint:
+// target}.
 func parseTarget(target string) (ret resolver.Target) {
-	ret.Scheme, ret.Endpoint = split2(target, "://")
-	ret.Authority, ret.Endpoint = split2(ret.Endpoint, "/")
+	var ok bool
+	ret.Scheme, ret.Endpoint, ok = split2(target, "://")
+	if !ok {
+		return resolver.Target{Endpoint: target}
+	}
+	ret.Authority, ret.Endpoint, ok = split2(ret.Endpoint, "/")
+	if !ok {
+		return resolver.Target{Endpoint: target}
+	}
 	return ret
 }
 
 // newCCResolverWrapper parses cc.target for scheme and gets the resolver
-// builder for this scheme. It then builds the resolver and starts the
-// monitoring goroutine for it.
+// builder for this scheme and builds the resolver. The monitoring goroutine
+// for it is not started yet and can be created by calling start().
 //
-// This function could return nil, nil, in tests for old behaviors.
-// TODO(bar) never return nil, nil when DNS becomes the default resolver.
+// If withResolverBuilder dial option is set, the specified resolver will be
+// used instead.
 func newCCResolverWrapper(cc *ClientConn) (*ccResolverWrapper, error) {
-	target := parseTarget(cc.target)
-	grpclog.Infof("dialing to target with scheme: %q", target.Scheme)
-
-	rb := resolver.Get(target.Scheme)
+	rb := cc.dopts.resolverBuilder
 	if rb == nil {
-		// TODO(bar) return error when DNS becomes the default (implemented and
-		// registered by DNS package).
-		grpclog.Infof("could not get resolver for scheme: %q", target.Scheme)
-		return nil, nil
+		return nil, fmt.Errorf("could not get resolver for scheme: %q", cc.parsedTarget.Scheme)
 	}
 
 	ccr := &ccResolverWrapper{
@@ -79,15 +84,18 @@ func newCCResolverWrapper(cc *ClientConn) (*ccResolverWrapper, error) {
 	}
 
 	var err error
-	ccr.resolver, err = rb.Build(target, ccr, resolver.BuildOption{})
+	ccr.resolver, err = rb.Build(cc.parsedTarget, ccr, resolver.BuildOption{DisableServiceConfig: cc.dopts.disableServiceConfig})
 	if err != nil {
 		return nil, err
 	}
-	go ccr.watcher()
 	return ccr, nil
 }
 
-// watcher processes address updates and service config updates sequencially.
+func (ccr *ccResolverWrapper) start() {
+	go ccr.watcher()
+}
+
+// watcher processes address updates and service config updates sequentially.
 // Otherwise, we need to resolve possible races between address and service
 // config (e.g. they specify different balancer types).
 func (ccr *ccResolverWrapper) watcher() {
@@ -100,20 +108,31 @@ func (ccr *ccResolverWrapper) watcher() {
 
 		select {
 		case addrs := <-ccr.addrCh:
-			grpclog.Infof("ccResolverWrapper: sending new addresses to balancer wrapper: %v", addrs)
-			// TODO(bar switching) this should never be nil. Pickfirst should be default.
-			if ccr.cc.balancerWrapper != nil {
-				// TODO(bar switching) create balancer if it's nil?
-				ccr.cc.balancerWrapper.handleResolvedAddrs(addrs, nil)
+			select {
+			case <-ccr.done:
+				return
+			default:
 			}
+			grpclog.Infof("ccResolverWrapper: sending new addresses to cc: %v", addrs)
+			ccr.cc.handleResolvedAddrs(addrs, nil)
 		case sc := <-ccr.scCh:
+			select {
+			case <-ccr.done:
+				return
+			default:
+			}
 			grpclog.Infof("ccResolverWrapper: got new service config: %v", sc)
+			ccr.cc.handleServiceConfig(sc)
 		case <-ccr.done:
 			return
 		}
 	}
 }
 
+func (ccr *ccResolverWrapper) resolveNow(o resolver.ResolveNowOption) {
+	ccr.resolver.ResolveNow(o)
+}
+
 func (ccr *ccResolverWrapper) close() {
 	ccr.resolver.Close()
 	close(ccr.done)
@@ -129,7 +148,7 @@ func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
 }
 
 // NewServiceConfig is called by the resolver implemenetion to send service
-// configs to gPRC.
+// configs to gRPC.
 func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
 	select {
 	case <-ccr.scCh:
diff --git a/vendor/google.golang.org/grpc/rpc_util.go b/vendor/google.golang.org/grpc/rpc_util.go
index 1703661..033801f 100644
--- a/vendor/google.golang.org/grpc/rpc_util.go
+++ b/vendor/google.golang.org/grpc/rpc_util.go
@@ -21,18 +21,21 @@ package grpc
 import (
 	"bytes"
 	"compress/gzip"
-	stdctx "context"
 	"encoding/binary"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"math"
-	"os"
+	"net/url"
+	"strings"
 	"sync"
 	"time"
 
 	"golang.org/x/net/context"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/encoding/proto"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/peer"
 	"google.golang.org/grpc/stats"
@@ -41,6 +44,8 @@ import (
 )
 
 // Compressor defines the interface gRPC uses to compress a message.
+//
+// Deprecated: use package encoding.
 type Compressor interface {
 	// Do compresses p into w.
 	Do(w io.Writer, p []byte) error
@@ -53,14 +58,34 @@ type gzipCompressor struct {
 }
 
 // NewGZIPCompressor creates a Compressor based on GZIP.
+//
+// Deprecated: use package encoding/gzip.
 func NewGZIPCompressor() Compressor {
+	c, _ := NewGZIPCompressorWithLevel(gzip.DefaultCompression)
+	return c
+}
+
+// NewGZIPCompressorWithLevel is like NewGZIPCompressor but specifies the gzip compression level instead
+// of assuming DefaultCompression.
+//
+// The error returned will be nil if the level is valid.
+//
+// Deprecated: use package encoding/gzip.
+func NewGZIPCompressorWithLevel(level int) (Compressor, error) {
+	if level < gzip.DefaultCompression || level > gzip.BestCompression {
+		return nil, fmt.Errorf("grpc: invalid compression level: %d", level)
+	}
 	return &gzipCompressor{
 		pool: sync.Pool{
 			New: func() interface{} {
-				return gzip.NewWriter(ioutil.Discard)
+				w, err := gzip.NewWriterLevel(ioutil.Discard, level)
+				if err != nil {
+					panic(err)
+				}
+				return w
 			},
 		},
-	}
+	}, nil
 }
 
 func (c *gzipCompressor) Do(w io.Writer, p []byte) error {
@@ -78,6 +103,8 @@ func (c *gzipCompressor) Type() string {
 }
 
 // Decompressor defines the interface gRPC uses to decompress a message.
+//
+// Deprecated: use package encoding.
 type Decompressor interface {
 	// Do reads the data from r and uncompress them.
 	Do(r io.Reader) ([]byte, error)
@@ -90,6 +117,8 @@ type gzipDecompressor struct {
 }
 
 // NewGZIPDecompressor creates a Decompressor based on GZIP.
+//
+// Deprecated: use package encoding/gzip.
 func NewGZIPDecompressor() Decompressor {
 	return &gzipDecompressor{}
 }
@@ -124,14 +153,15 @@ func (d *gzipDecompressor) Type() string {
 
 // callInfo contains all related configuration and information about an RPC.
 type callInfo struct {
+	compressorType        string
 	failFast              bool
-	headerMD              metadata.MD
-	trailerMD             metadata.MD
-	peer                  *peer.Peer
+	stream                *clientStream
 	traceInfo             traceInfo // in trace.go
 	maxReceiveMessageSize *int
 	maxSendMessageSize    *int
 	creds                 credentials.PerRPCCredentials
+	contentSubtype        string
+	codec                 baseCodec
 }
 
 func defaultCallInfo() *callInfo {
@@ -158,86 +188,239 @@ type EmptyCallOption struct{}
 func (EmptyCallOption) before(*callInfo) error { return nil }
 func (EmptyCallOption) after(*callInfo)        {}
 
-type beforeCall func(c *callInfo) error
-
-func (o beforeCall) before(c *callInfo) error { return o(c) }
-func (o beforeCall) after(c *callInfo)        {}
-
-type afterCall func(c *callInfo)
-
-func (o afterCall) before(c *callInfo) error { return nil }
-func (o afterCall) after(c *callInfo)        { o(c) }
-
 // Header returns a CallOptions that retrieves the header metadata
 // for a unary RPC.
 func Header(md *metadata.MD) CallOption {
-	return afterCall(func(c *callInfo) {
-		*md = c.headerMD
-	})
+	return HeaderCallOption{HeaderAddr: md}
+}
+
+// HeaderCallOption is a CallOption for collecting response header metadata.
+// The metadata field will be populated *after* the RPC completes.
+// This is an EXPERIMENTAL API.
+type HeaderCallOption struct {
+	HeaderAddr *metadata.MD
+}
+
+func (o HeaderCallOption) before(c *callInfo) error { return nil }
+func (o HeaderCallOption) after(c *callInfo) {
+	if c.stream != nil {
+		*o.HeaderAddr, _ = c.stream.Header()
+	}
 }
 
 // Trailer returns a CallOptions that retrieves the trailer metadata
 // for a unary RPC.
 func Trailer(md *metadata.MD) CallOption {
-	return afterCall(func(c *callInfo) {
-		*md = c.trailerMD
-	})
+	return TrailerCallOption{TrailerAddr: md}
 }
 
-// Peer returns a CallOption that retrieves peer information for a
-// unary RPC.
-func Peer(peer *peer.Peer) CallOption {
-	return afterCall(func(c *callInfo) {
-		if c.peer != nil {
-			*peer = *c.peer
+// TrailerCallOption is a CallOption for collecting response trailer metadata.
+// The metadata field will be populated *after* the RPC completes.
+// This is an EXPERIMENTAL API.
+type TrailerCallOption struct {
+	TrailerAddr *metadata.MD
+}
+
+func (o TrailerCallOption) before(c *callInfo) error { return nil }
+func (o TrailerCallOption) after(c *callInfo) {
+	if c.stream != nil {
+		*o.TrailerAddr = c.stream.Trailer()
+	}
+}
+
+// Peer returns a CallOption that retrieves peer information for a unary RPC.
+// The peer field will be populated *after* the RPC completes.
+func Peer(p *peer.Peer) CallOption {
+	return PeerCallOption{PeerAddr: p}
+}
+
+// PeerCallOption is a CallOption for collecting the identity of the remote
+// peer. The peer field will be populated *after* the RPC completes.
+// This is an EXPERIMENTAL API.
+type PeerCallOption struct {
+	PeerAddr *peer.Peer
+}
+
+func (o PeerCallOption) before(c *callInfo) error { return nil }
+func (o PeerCallOption) after(c *callInfo) {
+	if c.stream != nil {
+		if x, ok := peer.FromContext(c.stream.Context()); ok {
+			*o.PeerAddr = *x
 		}
-	})
+	}
 }
 
 // FailFast configures the action to take when an RPC is attempted on broken
-// connections or unreachable servers. If failFast is true, the RPC will fail
+// connections or unreachable servers.  If failFast is true, the RPC will fail
 // immediately. Otherwise, the RPC client will block the call until a
-// connection is available (or the call is canceled or times out). Please refer
-// to https://github.com/grpc/grpc/blob/master/doc/wait-for-ready.md.
-// The default behavior of RPCs is to fail fast.
+// connection is available (or the call is canceled or times out) and will
+// retry the call if it fails due to a transient error.  gRPC will not retry if
+// data was written to the wire unless the server indicates it did not process
+// the data.  Please refer to
+// https://github.com/grpc/grpc/blob/master/doc/wait-for-ready.md.
+//
+// By default, RPCs are "Fail Fast".
 func FailFast(failFast bool) CallOption {
-	return beforeCall(func(c *callInfo) error {
-		c.failFast = failFast
-		return nil
-	})
+	return FailFastCallOption{FailFast: failFast}
 }
 
+// FailFastCallOption is a CallOption for indicating whether an RPC should fail
+// fast or not.
+// This is an EXPERIMENTAL API.
+type FailFastCallOption struct {
+	FailFast bool
+}
+
+func (o FailFastCallOption) before(c *callInfo) error {
+	c.failFast = o.FailFast
+	return nil
+}
+func (o FailFastCallOption) after(c *callInfo) {}
+
 // MaxCallRecvMsgSize returns a CallOption which sets the maximum message size the client can receive.
 func MaxCallRecvMsgSize(s int) CallOption {
-	return beforeCall(func(o *callInfo) error {
-		o.maxReceiveMessageSize = &s
-		return nil
-	})
+	return MaxRecvMsgSizeCallOption{MaxRecvMsgSize: s}
+}
+
+// MaxRecvMsgSizeCallOption is a CallOption that indicates the maximum message
+// size the client can receive.
+// This is an EXPERIMENTAL API.
+type MaxRecvMsgSizeCallOption struct {
+	MaxRecvMsgSize int
 }
 
+func (o MaxRecvMsgSizeCallOption) before(c *callInfo) error {
+	c.maxReceiveMessageSize = &o.MaxRecvMsgSize
+	return nil
+}
+func (o MaxRecvMsgSizeCallOption) after(c *callInfo) {}
+
 // MaxCallSendMsgSize returns a CallOption which sets the maximum message size the client can send.
 func MaxCallSendMsgSize(s int) CallOption {
-	return beforeCall(func(o *callInfo) error {
-		o.maxSendMessageSize = &s
-		return nil
-	})
+	return MaxSendMsgSizeCallOption{MaxSendMsgSize: s}
+}
+
+// MaxSendMsgSizeCallOption is a CallOption that indicates the maximum message
+// size the client can send.
+// This is an EXPERIMENTAL API.
+type MaxSendMsgSizeCallOption struct {
+	MaxSendMsgSize int
+}
+
+func (o MaxSendMsgSizeCallOption) before(c *callInfo) error {
+	c.maxSendMessageSize = &o.MaxSendMsgSize
+	return nil
 }
+func (o MaxSendMsgSizeCallOption) after(c *callInfo) {}
 
 // PerRPCCredentials returns a CallOption that sets credentials.PerRPCCredentials
 // for a call.
 func PerRPCCredentials(creds credentials.PerRPCCredentials) CallOption {
-	return beforeCall(func(c *callInfo) error {
-		c.creds = creds
-		return nil
-	})
+	return PerRPCCredsCallOption{Creds: creds}
+}
+
+// PerRPCCredsCallOption is a CallOption that indicates the per-RPC
+// credentials to use for the call.
+// This is an EXPERIMENTAL API.
+type PerRPCCredsCallOption struct {
+	Creds credentials.PerRPCCredentials
+}
+
+func (o PerRPCCredsCallOption) before(c *callInfo) error {
+	c.creds = o.Creds
+	return nil
+}
+func (o PerRPCCredsCallOption) after(c *callInfo) {}
+
+// UseCompressor returns a CallOption which sets the compressor used when
+// sending the request.  If WithCompressor is also set, UseCompressor has
+// higher priority.
+//
+// This API is EXPERIMENTAL.
+func UseCompressor(name string) CallOption {
+	return CompressorCallOption{CompressorType: name}
 }
 
+// CompressorCallOption is a CallOption that indicates the compressor to use.
+// This is an EXPERIMENTAL API.
+type CompressorCallOption struct {
+	CompressorType string
+}
+
+func (o CompressorCallOption) before(c *callInfo) error {
+	c.compressorType = o.CompressorType
+	return nil
+}
+func (o CompressorCallOption) after(c *callInfo) {}
+
+// CallContentSubtype returns a CallOption that will set the content-subtype
+// for a call. For example, if content-subtype is "json", the Content-Type over
+// the wire will be "application/grpc+json". The content-subtype is converted
+// to lowercase before being included in Content-Type. See Content-Type on
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+//
+// If CallCustomCodec is not also used, the content-subtype will be used to
+// look up the Codec to use in the registry controlled by RegisterCodec. See
+// the documentation on RegisterCodec for details on registration. The lookup
+// of content-subtype is case-insensitive. If no such Codec is found, the call
+// will result in an error with code codes.Internal.
+//
+// If CallCustomCodec is also used, that Codec will be used for all request and
+// response messages, with the content-subtype set to the given contentSubtype
+// here for requests.
+func CallContentSubtype(contentSubtype string) CallOption {
+	return ContentSubtypeCallOption{ContentSubtype: strings.ToLower(contentSubtype)}
+}
+
+// ContentSubtypeCallOption is a CallOption that indicates the content-subtype
+// used for marshaling messages.
+// This is an EXPERIMENTAL API.
+type ContentSubtypeCallOption struct {
+	ContentSubtype string
+}
+
+func (o ContentSubtypeCallOption) before(c *callInfo) error {
+	c.contentSubtype = o.ContentSubtype
+	return nil
+}
+func (o ContentSubtypeCallOption) after(c *callInfo) {}
+
+// CallCustomCodec returns a CallOption that will set the given Codec to be
+// used for all request and response messages for a call. The result of calling
+// String() will be used as the content-subtype in a case-insensitive manner.
+//
+// See Content-Type on
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details. Also see the documentation on RegisterCodec and
+// CallContentSubtype for more details on the interaction between Codec and
+// content-subtype.
+//
+// This function is provided for advanced users; prefer to use only
+// CallContentSubtype to select a registered codec instead.
+func CallCustomCodec(codec Codec) CallOption {
+	return CustomCodecCallOption{Codec: codec}
+}
+
+// CustomCodecCallOption is a CallOption that indicates the codec used for
+// marshaling messages.
+// This is an EXPERIMENTAL API.
+type CustomCodecCallOption struct {
+	Codec Codec
+}
+
+func (o CustomCodecCallOption) before(c *callInfo) error {
+	c.codec = o.Codec
+	return nil
+}
+func (o CustomCodecCallOption) after(c *callInfo) {}
+
 // The format of the payload: compressed or not?
 type payloadFormat uint8
 
 const (
-	compressionNone payloadFormat = iota // no compression
-	compressionMade
+	compressionNone payloadFormat = 0 // no compression
+	compressionMade payloadFormat = 1 // compressed
 )
 
 // parser reads complete gRPC messages from the underlying reader.
@@ -247,8 +430,8 @@ type parser struct {
 	// error types.
 	r io.Reader
 
-	// The header of a gRPC message. Find more detail
-	// at https://grpc.io/docs/guides/wire.html.
+	// The header of a gRPC message. Find more detail at
+	// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md
 	header [5]byte
 }
 
@@ -276,8 +459,11 @@ func (p *parser) recvMsg(maxReceiveMessageSize int) (pf payloadFormat, msg []byt
 	if length == 0 {
 		return pf, nil, nil
 	}
-	if length > uint32(maxReceiveMessageSize) {
-		return 0, nil, Errorf(codes.ResourceExhausted, "grpc: received message larger than max (%d vs. %d)", length, maxReceiveMessageSize)
+	if int64(length) > int64(maxInt) {
+		return 0, nil, status.Errorf(codes.ResourceExhausted, "grpc: received message larger than max length allowed on current machine (%d vs. %d)", length, maxInt)
+	}
+	if int(length) > maxReceiveMessageSize {
+		return 0, nil, status.Errorf(codes.ResourceExhausted, "grpc: received message larger than max (%d vs. %d)", length, maxReceiveMessageSize)
 	}
 	// TODO(bradfitz,zhaoq): garbage. reuse buffer after proto decoding instead
 	// of making it for each message:
@@ -291,67 +477,104 @@ func (p *parser) recvMsg(maxReceiveMessageSize int) (pf payloadFormat, msg []byt
 	return pf, msg, nil
 }
 
-// encode serializes msg and returns a buffer of message header and a buffer of msg.
-// If msg is nil, it generates the message header and an empty msg buffer.
-func encode(c Codec, msg interface{}, cp Compressor, cbuf *bytes.Buffer, outPayload *stats.OutPayload) ([]byte, []byte, error) {
-	var b []byte
-	const (
-		payloadLen = 1
-		sizeLen    = 4
-	)
+// encode serializes msg and returns a buffer containing the message, or an
+// error if it is too large to be transmitted by grpc.  If msg is nil, it
+// generates an empty message.
+func encode(c baseCodec, msg interface{}) ([]byte, error) {
+	if msg == nil { // NOTE: typed nils will not be caught by this check
+		return nil, nil
+	}
+	b, err := c.Marshal(msg)
+	if err != nil {
+		return nil, status.Errorf(codes.Internal, "grpc: error while marshaling: %v", err.Error())
+	}
+	if uint(len(b)) > math.MaxUint32 {
+		return nil, status.Errorf(codes.ResourceExhausted, "grpc: message too large (%d bytes)", len(b))
+	}
+	return b, nil
+}
 
-	if msg != nil {
-		var err error
-		b, err = c.Marshal(msg)
-		if err != nil {
-			return nil, nil, Errorf(codes.Internal, "grpc: error while marshaling: %v", err.Error())
+// compress returns the input bytes compressed by compressor or cp.  If both
+// compressors are nil, returns nil.
+//
+// TODO(dfawley): eliminate cp parameter by wrapping Compressor in an encoding.Compressor.
+func compress(in []byte, cp Compressor, compressor encoding.Compressor) ([]byte, error) {
+	if compressor == nil && cp == nil {
+		return nil, nil
+	}
+	wrapErr := func(err error) error {
+		return status.Errorf(codes.Internal, "grpc: error while compressing: %v", err.Error())
+	}
+	cbuf := &bytes.Buffer{}
+	if compressor != nil {
+		z, _ := compressor.Compress(cbuf)
+		if _, err := z.Write(in); err != nil {
+			return nil, wrapErr(err)
 		}
-		if outPayload != nil {
-			outPayload.Payload = msg
-			// TODO truncate large payload.
-			outPayload.Data = b
-			outPayload.Length = len(b)
+		if err := z.Close(); err != nil {
+			return nil, wrapErr(err)
 		}
-		if cp != nil {
-			if err := cp.Do(cbuf, b); err != nil {
-				return nil, nil, Errorf(codes.Internal, "grpc: error while compressing: %v", err.Error())
-			}
-			b = cbuf.Bytes()
+	} else {
+		if err := cp.Do(cbuf, in); err != nil {
+			return nil, wrapErr(err)
 		}
 	}
+	return cbuf.Bytes(), nil
+}
 
-	if uint(len(b)) > math.MaxUint32 {
-		return nil, nil, Errorf(codes.ResourceExhausted, "grpc: message too large (%d bytes)", len(b))
-	}
+const (
+	payloadLen = 1
+	sizeLen    = 4
+	headerLen  = payloadLen + sizeLen
+)
 
-	bufHeader := make([]byte, payloadLen+sizeLen)
-	if cp == nil {
-		bufHeader[0] = byte(compressionNone)
+// msgHeader returns a 5-byte header for the message being transmitted and the
+// payload, which is compData if non-nil or data otherwise.
+func msgHeader(data, compData []byte) (hdr []byte, payload []byte) {
+	hdr = make([]byte, headerLen)
+	if compData != nil {
+		hdr[0] = byte(compressionMade)
+		data = compData
 	} else {
-		bufHeader[0] = byte(compressionMade)
+		hdr[0] = byte(compressionNone)
 	}
-	// Write length of b into buf
-	binary.BigEndian.PutUint32(bufHeader[payloadLen:], uint32(len(b)))
-	if outPayload != nil {
-		outPayload.WireLength = payloadLen + sizeLen + len(b)
+
+	// Write length of payload into buf
+	binary.BigEndian.PutUint32(hdr[payloadLen:], uint32(len(data)))
+	return hdr, data
+}
+
+func outPayload(client bool, msg interface{}, data, payload []byte, t time.Time) *stats.OutPayload {
+	return &stats.OutPayload{
+		Client:     client,
+		Payload:    msg,
+		Data:       data,
+		Length:     len(data),
+		WireLength: len(payload) + headerLen,
+		SentTime:   t,
 	}
-	return bufHeader, b, nil
 }
 
-func checkRecvPayload(pf payloadFormat, recvCompress string, dc Decompressor) error {
+func checkRecvPayload(pf payloadFormat, recvCompress string, haveCompressor bool) *status.Status {
 	switch pf {
 	case compressionNone:
 	case compressionMade:
-		if dc == nil || recvCompress != dc.Type() {
-			return Errorf(codes.Unimplemented, "grpc: Decompressor is not installed for grpc-encoding %q", recvCompress)
+		if recvCompress == "" || recvCompress == encoding.Identity {
+			return status.New(codes.Internal, "grpc: compressed flag set with identity or empty encoding")
+		}
+		if !haveCompressor {
+			return status.Newf(codes.Unimplemented, "grpc: Decompressor is not installed for grpc-encoding %q", recvCompress)
 		}
 	default:
-		return Errorf(codes.Internal, "grpc: received unexpected payload format %d", pf)
+		return status.Newf(codes.Internal, "grpc: received unexpected payload format %d", pf)
 	}
 	return nil
 }
 
-func recv(p *parser, c Codec, s *transport.Stream, dc Decompressor, m interface{}, maxReceiveMessageSize int, inPayload *stats.InPayload) error {
+// For the two compressor parameters, both should not be set, but if they are,
+// dc takes precedence over compressor.
+// TODO(dfawley): wrap the old compressor/decompressor using the new API?
+func recv(p *parser, c baseCodec, s *transport.Stream, dc Decompressor, m interface{}, maxReceiveMessageSize int, inPayload *stats.InPayload, compressor encoding.Compressor) error {
 	pf, d, err := p.recvMsg(maxReceiveMessageSize)
 	if err != nil {
 		return err
@@ -359,22 +582,37 @@ func recv(p *parser, c Codec, s *transport.Stream, dc Decompressor, m interface{
 	if inPayload != nil {
 		inPayload.WireLength = len(d)
 	}
-	if err := checkRecvPayload(pf, s.RecvCompress(), dc); err != nil {
-		return err
+
+	if st := checkRecvPayload(pf, s.RecvCompress(), compressor != nil || dc != nil); st != nil {
+		return st.Err()
 	}
+
 	if pf == compressionMade {
-		d, err = dc.Do(bytes.NewReader(d))
-		if err != nil {
-			return Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
+		// To match legacy behavior, if the decompressor is set by WithDecompressor or RPCDecompressor,
+		// use this decompressor as the default.
+		if dc != nil {
+			d, err = dc.Do(bytes.NewReader(d))
+			if err != nil {
+				return status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
+			}
+		} else {
+			dcReader, err := compressor.Decompress(bytes.NewReader(d))
+			if err != nil {
+				return status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
+			}
+			d, err = ioutil.ReadAll(dcReader)
+			if err != nil {
+				return status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
+			}
 		}
 	}
 	if len(d) > maxReceiveMessageSize {
 		// TODO: Revisit the error code. Currently keep it consistent with java
 		// implementation.
-		return Errorf(codes.ResourceExhausted, "grpc: received message larger than max (%d vs. %d)", len(d), maxReceiveMessageSize)
+		return status.Errorf(codes.ResourceExhausted, "grpc: received message larger than max (%d vs. %d)", len(d), maxReceiveMessageSize)
 	}
 	if err := c.Unmarshal(d, m); err != nil {
-		return Errorf(codes.Internal, "grpc: failed to unmarshal the received message %v", err)
+		return status.Errorf(codes.Internal, "grpc: failed to unmarshal the received message %v", err)
 	}
 	if inPayload != nil {
 		inPayload.RecvTime = time.Now()
@@ -387,9 +625,7 @@ func recv(p *parser, c Codec, s *transport.Stream, dc Decompressor, m interface{
 }
 
 type rpcInfo struct {
-	failfast      bool
-	bytesSent     bool
-	bytesReceived bool
+	failfast bool
 }
 
 type rpcInfoContextKey struct{}
@@ -403,69 +639,10 @@ func rpcInfoFromContext(ctx context.Context) (s *rpcInfo, ok bool) {
 	return
 }
 
-func updateRPCInfoInContext(ctx context.Context, s rpcInfo) {
-	if ss, ok := rpcInfoFromContext(ctx); ok {
-		ss.bytesReceived = s.bytesReceived
-		ss.bytesSent = s.bytesSent
-	}
-	return
-}
-
-// toRPCErr converts an error into an error from the status package.
-func toRPCErr(err error) error {
-	if _, ok := status.FromError(err); ok {
-		return err
-	}
-	switch e := err.(type) {
-	case transport.StreamError:
-		return status.Error(e.Code, e.Desc)
-	case transport.ConnectionError:
-		return status.Error(codes.Unavailable, e.Desc)
-	default:
-		switch err {
-		case context.DeadlineExceeded, stdctx.DeadlineExceeded:
-			return status.Error(codes.DeadlineExceeded, err.Error())
-		case context.Canceled, stdctx.Canceled:
-			return status.Error(codes.Canceled, err.Error())
-		case ErrClientConnClosing:
-			return status.Error(codes.FailedPrecondition, err.Error())
-		}
-	}
-	return status.Error(codes.Unknown, err.Error())
-}
-
-// convertCode converts a standard Go error into its canonical code. Note that
-// this is only used to translate the error returned by the server applications.
-func convertCode(err error) codes.Code {
-	switch err {
-	case nil:
-		return codes.OK
-	case io.EOF:
-		return codes.OutOfRange
-	case io.ErrClosedPipe, io.ErrNoProgress, io.ErrShortBuffer, io.ErrShortWrite, io.ErrUnexpectedEOF:
-		return codes.FailedPrecondition
-	case os.ErrInvalid:
-		return codes.InvalidArgument
-	case context.Canceled, stdctx.Canceled:
-		return codes.Canceled
-	case context.DeadlineExceeded, stdctx.DeadlineExceeded:
-		return codes.DeadlineExceeded
-	}
-	switch {
-	case os.IsExist(err):
-		return codes.AlreadyExists
-	case os.IsNotExist(err):
-		return codes.NotFound
-	case os.IsPermission(err):
-		return codes.PermissionDenied
-	}
-	return codes.Unknown
-}
-
 // Code returns the error code for err if it was produced by the rpc system.
 // Otherwise, it returns codes.Unknown.
 //
-// Deprecated; use status.FromError and Code method instead.
+// Deprecated: use status.FromError and Code method instead.
 func Code(err error) codes.Code {
 	if s, ok := status.FromError(err); ok {
 		return s.Code()
@@ -476,7 +653,7 @@ func Code(err error) codes.Code {
 // ErrorDesc returns the error description of err if it was produced by the rpc system.
 // Otherwise, it returns err.Error() or empty string when err is nil.
 //
-// Deprecated; use status.FromError and Message method instead.
+// Deprecated: use status.FromError and Message method instead.
 func ErrorDesc(err error) string {
 	if s, ok := status.FromError(err); ok {
 		return s.Message()
@@ -487,85 +664,78 @@ func ErrorDesc(err error) string {
 // Errorf returns an error containing an error code and a description;
 // Errorf returns nil if c is OK.
 //
-// Deprecated; use status.Errorf instead.
+// Deprecated: use status.Errorf instead.
 func Errorf(c codes.Code, format string, a ...interface{}) error {
 	return status.Errorf(c, format, a...)
 }
 
-// MethodConfig defines the configuration recommended by the service providers for a
-// particular method.
-// This is EXPERIMENTAL and subject to change.
-type MethodConfig struct {
-	// WaitForReady indicates whether RPCs sent to this method should wait until
-	// the connection is ready by default (!failfast). The value specified via the
-	// gRPC client API will override the value set here.
-	WaitForReady *bool
-	// Timeout is the default timeout for RPCs sent to this method. The actual
-	// deadline used will be the minimum of the value specified here and the value
-	// set by the application via the gRPC client API.  If either one is not set,
-	// then the other will be used.  If neither is set, then the RPC has no deadline.
-	Timeout *time.Duration
-	// MaxReqSize is the maximum allowed payload size for an individual request in a
-	// stream (client->server) in bytes. The size which is measured is the serialized
-	// payload after per-message compression (but before stream compression) in bytes.
-	// The actual value used is the minimum of the value specified here and the value set
-	// by the application via the gRPC client API. If either one is not set, then the other
-	// will be used.  If neither is set, then the built-in default is used.
-	MaxReqSize *int
-	// MaxRespSize is the maximum allowed payload size for an individual response in a
-	// stream (server->client) in bytes.
-	MaxRespSize *int
-}
-
-// ServiceConfig is provided by the service provider and contains parameters for how
-// clients that connect to the service should behave.
-// This is EXPERIMENTAL and subject to change.
-type ServiceConfig struct {
-	// LB is the load balancer the service providers recommends. The balancer specified
-	// via grpc.WithBalancer will override this.
-	LB Balancer
-	// Methods contains a map for the methods in this service.
-	// If there is an exact match for a method (i.e. /service/method) in the map, use the corresponding MethodConfig.
-	// If there's no exact match, look for the default config for the service (/service/) and use the corresponding MethodConfig if it exists.
-	// Otherwise, the method has no MethodConfig to use.
-	Methods map[string]MethodConfig
-}
-
-func min(a, b *int) *int {
-	if *a < *b {
-		return a
-	}
-	return b
-}
-
-func getMaxSize(mcMax, doptMax *int, defaultVal int) *int {
-	if mcMax == nil && doptMax == nil {
-		return &defaultVal
-	}
-	if mcMax != nil && doptMax != nil {
-		return min(mcMax, doptMax)
-	}
-	if mcMax != nil {
-		return mcMax
-	}
-	return doptMax
-}
-
-// SupportPackageIsVersion3 is referenced from generated protocol buffer files.
-// The latest support package version is 4.
-// SupportPackageIsVersion3 is kept for compatibility. It will be removed in the
-// next support package version update.
-const SupportPackageIsVersion3 = true
-
-// SupportPackageIsVersion4 is referenced from generated protocol buffer files
-// to assert that that code is compatible with this version of the grpc package.
-//
-// This constant may be renamed in the future if a change in the generated code
-// requires a synchronised update of grpc-go and protoc-gen-go. This constant
-// should not be referenced from any other code.
-const SupportPackageIsVersion4 = true
+// setCallInfoCodec should only be called after CallOptions have been applied.
+func setCallInfoCodec(c *callInfo) error {
+	if c.codec != nil {
+		// codec was already set by a CallOption; use it.
+		return nil
+	}
 
-// Version is the current grpc version.
-const Version = "1.8.0-dev"
+	if c.contentSubtype == "" {
+		// No codec specified in CallOptions; use proto by default.
+		c.codec = encoding.GetCodec(proto.Name)
+		return nil
+	}
+
+	// c.contentSubtype is already lowercased in CallContentSubtype
+	c.codec = encoding.GetCodec(c.contentSubtype)
+	if c.codec == nil {
+		return status.Errorf(codes.Internal, "no codec registered for content-subtype %s", c.contentSubtype)
+	}
+	return nil
+}
+
+// parseDialTarget returns the network and address to pass to dialer
+func parseDialTarget(target string) (net string, addr string) {
+	net = "tcp"
+
+	m1 := strings.Index(target, ":")
+	m2 := strings.Index(target, ":/")
+
+	// handle unix:addr which will fail with url.Parse
+	if m1 >= 0 && m2 < 0 {
+		if n := target[0:m1]; n == "unix" {
+			net = n
+			addr = target[m1+1:]
+			return net, addr
+		}
+	}
+	if m2 >= 0 {
+		t, err := url.Parse(target)
+		if err != nil {
+			return net, target
+		}
+		scheme := t.Scheme
+		addr = t.Path
+		if scheme == "unix" {
+			net = scheme
+			if addr == "" {
+				addr = t.Host
+			}
+			return net, addr
+		}
+	}
+
+	return net, target
+}
+
+// The SupportPackageIsVersion variables are referenced from generated protocol
+// buffer files to ensure compatibility with the gRPC version used.  The latest
+// support package version is 5.
+//
+// Older versions are kept for compatibility. They may be removed if
+// compatibility cannot be maintained.
+//
+// These constants should not be referenced from any other code.
+const (
+	SupportPackageIsVersion3 = true
+	SupportPackageIsVersion4 = true
+	SupportPackageIsVersion5 = true
+)
 
 const grpcUA = "grpc-go/" + Version
diff --git a/vendor/google.golang.org/grpc/server.go b/vendor/google.golang.org/grpc/server.go
index 7c882db..014c72b 100644
--- a/vendor/google.golang.org/grpc/server.go
+++ b/vendor/google.golang.org/grpc/server.go
@@ -32,13 +32,19 @@ import (
 	"sync"
 	"time"
 
+	"io/ioutil"
+
 	"golang.org/x/net/context"
 	"golang.org/x/net/http2"
 	"golang.org/x/net/trace"
+
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/encoding/proto"
 	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/internal"
+	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/stats"
@@ -89,18 +95,28 @@ type Server struct {
 	conns  map[io.Closer]bool
 	serve  bool
 	drain  bool
-	ctx    context.Context
-	cancel context.CancelFunc
-	// A CondVar to let GracefulStop() blocks until all the pending RPCs are finished
-	// and all the transport goes away.
-	cv     *sync.Cond
+	cv     *sync.Cond          // signaled when connections close for GracefulStop
 	m      map[string]*service // service name -> service info
 	events trace.EventLog
+
+	quit               chan struct{}
+	done               chan struct{}
+	quitOnce           sync.Once
+	doneOnce           sync.Once
+	channelzRemoveOnce sync.Once
+	serveWG            sync.WaitGroup // counts active Serve goroutines for GracefulStop
+
+	channelzID          int64 // channelz unique identification number
+	czmu                sync.RWMutex
+	callsStarted        int64
+	callsFailed         int64
+	callsSucceeded      int64
+	lastCallStartedTime time.Time
 }
 
 type options struct {
 	creds                 credentials.TransportCredentials
-	codec                 Codec
+	codec                 baseCodec
 	cp                    Compressor
 	dc                    Decompressor
 	unaryInt              UnaryServerInterceptor
@@ -118,11 +134,13 @@ type options struct {
 	initialConnWindowSize int32
 	writeBufferSize       int
 	readBufferSize        int
+	connectionTimeout     time.Duration
 }
 
 var defaultServerOptions = options{
 	maxReceiveMessageSize: defaultServerMaxReceiveMessageSize,
 	maxSendMessageSize:    defaultServerMaxSendMessageSize,
+	connectionTimeout:     120 * time.Second,
 }
 
 // A ServerOption sets options such as credentials, codec and keepalive parameters, etc.
@@ -175,20 +193,32 @@ func KeepaliveEnforcementPolicy(kep keepalive.EnforcementPolicy) ServerOption {
 }
 
 // CustomCodec returns a ServerOption that sets a codec for message marshaling and unmarshaling.
+//
+// This will override any lookups by content-subtype for Codecs registered with RegisterCodec.
 func CustomCodec(codec Codec) ServerOption {
 	return func(o *options) {
 		o.codec = codec
 	}
 }
 
-// RPCCompressor returns a ServerOption that sets a compressor for outbound messages.
+// RPCCompressor returns a ServerOption that sets a compressor for outbound
+// messages.  For backward compatibility, all outbound messages will be sent
+// using this compressor, regardless of incoming message compression.  By
+// default, server messages will be sent using the same compressor with which
+// request messages were sent.
+//
+// Deprecated: use encoding.RegisterCompressor instead.
 func RPCCompressor(cp Compressor) ServerOption {
 	return func(o *options) {
 		o.cp = cp
 	}
 }
 
-// RPCDecompressor returns a ServerOption that sets a decompressor for inbound messages.
+// RPCDecompressor returns a ServerOption that sets a decompressor for inbound
+// messages.  It has higher priority than decompressors registered via
+// encoding.RegisterCompressor.
+//
+// Deprecated: use encoding.RegisterCompressor instead.
 func RPCDecompressor(dc Decompressor) ServerOption {
 	return func(o *options) {
 		o.dc = dc
@@ -196,7 +226,9 @@ func RPCDecompressor(dc Decompressor) ServerOption {
 }
 
 // MaxMsgSize returns a ServerOption to set the max message size in bytes the server can receive.
-// If this is not set, gRPC uses the default limit. Deprecated: use MaxRecvMsgSize instead.
+// If this is not set, gRPC uses the default limit.
+//
+// Deprecated: use MaxRecvMsgSize instead.
 func MaxMsgSize(m int) ServerOption {
 	return MaxRecvMsgSize(m)
 }
@@ -291,6 +323,18 @@ func UnknownServiceHandler(streamHandler StreamHandler) ServerOption {
 	}
 }
 
+// ConnectionTimeout returns a ServerOption that sets the timeout for
+// connection establishment (up to and including HTTP/2 handshaking) for all
+// new connections.  If this is not set, the default is 120 seconds.  A zero or
+// negative value will result in an immediate timeout.
+//
+// This API is EXPERIMENTAL.
+func ConnectionTimeout(d time.Duration) ServerOption {
+	return func(o *options) {
+		o.connectionTimeout = d
+	}
+}
+
 // NewServer creates a gRPC server which has no service registered and has not
 // started to accept requests yet.
 func NewServer(opt ...ServerOption) *Server {
@@ -298,22 +342,23 @@ func NewServer(opt ...ServerOption) *Server {
 	for _, o := range opt {
 		o(&opts)
 	}
-	if opts.codec == nil {
-		// Set the default codec.
-		opts.codec = protoCodec{}
-	}
 	s := &Server{
 		lis:   make(map[net.Listener]bool),
 		opts:  opts,
 		conns: make(map[io.Closer]bool),
 		m:     make(map[string]*service),
+		quit:  make(chan struct{}),
+		done:  make(chan struct{}),
 	}
 	s.cv = sync.NewCond(&s.mu)
-	s.ctx, s.cancel = context.WithCancel(context.Background())
 	if EnableTracing {
 		_, file, line, _ := runtime.Caller(1)
 		s.events = trace.NewEventLog("grpc.Server", fmt.Sprintf("%s:%d", file, line))
 	}
+
+	if channelz.IsOn() {
+		s.channelzID = channelz.RegisterServer(s, "")
+	}
 	return s
 }
 
@@ -418,11 +463,9 @@ func (s *Server) GetServiceInfo() map[string]ServiceInfo {
 	return ret
 }
 
-var (
-	// ErrServerStopped indicates that the operation is now illegal because of
-	// the server being stopped.
-	ErrServerStopped = errors.New("grpc: the server has been stopped")
-)
+// ErrServerStopped indicates that the operation is now illegal because of
+// the server being stopped.
+var ErrServerStopped = errors.New("grpc: the server has been stopped")
 
 func (s *Server) useTransportAuthenticator(rawConn net.Conn) (net.Conn, credentials.AuthInfo, error) {
 	if s.opts.creds == nil {
@@ -431,28 +474,66 @@ func (s *Server) useTransportAuthenticator(rawConn net.Conn) (net.Conn, credenti
 	return s.opts.creds.ServerHandshake(rawConn)
 }
 
+type listenSocket struct {
+	net.Listener
+	channelzID int64
+}
+
+func (l *listenSocket) ChannelzMetric() *channelz.SocketInternalMetric {
+	return &channelz.SocketInternalMetric{
+		LocalAddr: l.Listener.Addr(),
+	}
+}
+
+func (l *listenSocket) Close() error {
+	err := l.Listener.Close()
+	if channelz.IsOn() {
+		channelz.RemoveEntry(l.channelzID)
+	}
+	return err
+}
+
 // Serve accepts incoming connections on the listener lis, creating a new
 // ServerTransport and service goroutine for each. The service goroutines
 // read gRPC requests and then call the registered handlers to reply to them.
 // Serve returns when lis.Accept fails with fatal errors.  lis will be closed when
 // this method returns.
-// Serve always returns non-nil error.
+// Serve will return a non-nil error unless Stop or GracefulStop is called.
 func (s *Server) Serve(lis net.Listener) error {
 	s.mu.Lock()
 	s.printf("serving")
 	s.serve = true
 	if s.lis == nil {
+		// Serve called after Stop or GracefulStop.
 		s.mu.Unlock()
 		lis.Close()
 		return ErrServerStopped
 	}
-	s.lis[lis] = true
+
+	s.serveWG.Add(1)
+	defer func() {
+		s.serveWG.Done()
+		select {
+		// Stop or GracefulStop called; block until done and return nil.
+		case <-s.quit:
+			<-s.done
+		default:
+		}
+	}()
+
+	ls := &listenSocket{Listener: lis}
+	s.lis[ls] = true
+
+	if channelz.IsOn() {
+		ls.channelzID = channelz.RegisterListenSocket(ls, s.channelzID, "")
+	}
 	s.mu.Unlock()
+
 	defer func() {
 		s.mu.Lock()
-		if s.lis != nil && s.lis[lis] {
-			lis.Close()
-			delete(s.lis, lis)
+		if s.lis != nil && s.lis[ls] {
+			ls.Close()
+			delete(s.lis, ls)
 		}
 		s.mu.Unlock()
 	}()
@@ -479,36 +560,52 @@ func (s *Server) Serve(lis net.Listener) error {
 				timer := time.NewTimer(tempDelay)
 				select {
 				case <-timer.C:
-				case <-s.ctx.Done():
+				case <-s.quit:
+					timer.Stop()
+					return nil
 				}
-				timer.Stop()
 				continue
 			}
 			s.mu.Lock()
 			s.printf("done serving; Accept = %v", err)
 			s.mu.Unlock()
+
+			select {
+			case <-s.quit:
+				return nil
+			default:
+			}
 			return err
 		}
 		tempDelay = 0
-		// Start a new goroutine to deal with rawConn
-		// so we don't stall this Accept loop goroutine.
-		go s.handleRawConn(rawConn)
+		// Start a new goroutine to deal with rawConn so we don't stall this Accept
+		// loop goroutine.
+		//
+		// Make sure we account for the goroutine so GracefulStop doesn't nil out
+		// s.conns before this conn can be added.
+		s.serveWG.Add(1)
+		go func() {
+			s.handleRawConn(rawConn)
+			s.serveWG.Done()
+		}()
 	}
 }
 
-// handleRawConn is run in its own goroutine and handles a just-accepted
-// connection that has not had any I/O performed on it yet.
+// handleRawConn forks a goroutine to handle a just-accepted connection that
+// has not had any I/O performed on it yet.
 func (s *Server) handleRawConn(rawConn net.Conn) {
+	rawConn.SetDeadline(time.Now().Add(s.opts.connectionTimeout))
 	conn, authInfo, err := s.useTransportAuthenticator(rawConn)
 	if err != nil {
 		s.mu.Lock()
 		s.errorf("ServerHandshake(%q) failed: %v", rawConn.RemoteAddr(), err)
 		s.mu.Unlock()
 		grpclog.Warningf("grpc: Server.Serve failed to complete security handshake from %q: %v", rawConn.RemoteAddr(), err)
-		// If serverHandShake returns ErrConnDispatched, keep rawConn open.
+		// If serverHandshake returns ErrConnDispatched, keep rawConn open.
 		if err != credentials.ErrConnDispatched {
 			rawConn.Close()
 		}
+		rawConn.SetDeadline(time.Time{})
 		return
 	}
 
@@ -520,19 +617,33 @@ func (s *Server) handleRawConn(rawConn net.Conn) {
 	}
 	s.mu.Unlock()
 
+	var serve func()
+	c := conn.(io.Closer)
 	if s.opts.useHandlerImpl {
-		s.serveUsingHandler(conn)
+		serve = func() { s.serveUsingHandler(conn) }
 	} else {
-		s.serveHTTP2Transport(conn, authInfo)
+		// Finish handshaking (HTTP2)
+		st := s.newHTTP2Transport(conn, authInfo)
+		if st == nil {
+			return
+		}
+		c = st
+		serve = func() { s.serveStreams(st) }
 	}
+
+	rawConn.SetDeadline(time.Time{})
+	if !s.addConn(c) {
+		return
+	}
+	go func() {
+		serve()
+		s.removeConn(c)
+	}()
 }
 
-// serveHTTP2Transport sets up a http/2 transport (using the
-// gRPC http2 server transport in transport/http2_server.go) and
-// serves streams on it.
-// This is run in its own goroutine (it does network I/O in
-// transport.NewServerTransport).
-func (s *Server) serveHTTP2Transport(c net.Conn, authInfo credentials.AuthInfo) {
+// newHTTP2Transport sets up a http/2 transport (using the
+// gRPC http2 server transport in transport/http2_server.go).
+func (s *Server) newHTTP2Transport(c net.Conn, authInfo credentials.AuthInfo) transport.ServerTransport {
 	config := &transport.ServerConfig{
 		MaxStreams:            s.opts.maxConcurrentStreams,
 		AuthInfo:              authInfo,
@@ -544,6 +655,7 @@ func (s *Server) serveHTTP2Transport(c net.Conn, authInfo credentials.AuthInfo)
 		InitialConnWindowSize: s.opts.initialConnWindowSize,
 		WriteBufferSize:       s.opts.writeBufferSize,
 		ReadBufferSize:        s.opts.readBufferSize,
+		ChannelzParentID:      s.channelzID,
 	}
 	st, err := transport.NewServerTransport("http2", c, config)
 	if err != nil {
@@ -552,17 +664,13 @@ func (s *Server) serveHTTP2Transport(c net.Conn, authInfo credentials.AuthInfo)
 		s.mu.Unlock()
 		c.Close()
 		grpclog.Warningln("grpc: Server.Serve failed to create ServerTransport: ", err)
-		return
-	}
-	if !s.addConn(st) {
-		st.Close()
-		return
+		return nil
 	}
-	s.serveStreams(st)
+
+	return st
 }
 
 func (s *Server) serveStreams(st transport.ServerTransport) {
-	defer s.removeConn(st)
 	defer st.Close()
 	var wg sync.WaitGroup
 	st.HandleStreams(func(stream *transport.Stream) {
@@ -596,11 +704,6 @@ var _ http.Handler = (*Server)(nil)
 //
 // conn is the *tls.Conn that's already been authenticated.
 func (s *Server) serveUsingHandler(conn net.Conn) {
-	if !s.addConn(conn) {
-		conn.Close()
-		return
-	}
-	defer s.removeConn(conn)
 	h2s := &http2.Server{
 		MaxConcurrentStreams: s.opts.maxConcurrentStreams,
 	}
@@ -634,13 +737,12 @@ func (s *Server) serveUsingHandler(conn net.Conn) {
 // available through grpc-go's HTTP/2 server, and it is currently EXPERIMENTAL
 // and subject to change.
 func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	st, err := transport.NewServerHandlerTransport(w, r)
+	st, err := transport.NewServerHandlerTransport(w, r, s.opts.statsHandler)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 	if !s.addConn(st) {
-		st.Close()
 		return
 	}
 	defer s.removeConn(st)
@@ -670,9 +772,15 @@ func (s *Server) traceInfo(st transport.ServerTransport, stream *transport.Strea
 func (s *Server) addConn(c io.Closer) bool {
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	if s.conns == nil || s.drain {
+	if s.conns == nil {
+		c.Close()
 		return false
 	}
+	if s.drain {
+		// Transport added after we drained our existing conns: drain it
+		// immediately.
+		c.(transport.ServerTransport).Drain()
+	}
 	s.conns[c] = true
 	return true
 }
@@ -686,43 +794,83 @@ func (s *Server) removeConn(c io.Closer) {
 	}
 }
 
-func (s *Server) sendResponse(t transport.ServerTransport, stream *transport.Stream, msg interface{}, cp Compressor, opts *transport.Options) error {
-	var (
-		cbuf       *bytes.Buffer
-		outPayload *stats.OutPayload
-	)
-	if cp != nil {
-		cbuf = new(bytes.Buffer)
-	}
-	if s.opts.statsHandler != nil {
-		outPayload = &stats.OutPayload{}
+// ChannelzMetric returns ServerInternalMetric of current server.
+// This is an EXPERIMENTAL API.
+func (s *Server) ChannelzMetric() *channelz.ServerInternalMetric {
+	s.czmu.RLock()
+	defer s.czmu.RUnlock()
+	return &channelz.ServerInternalMetric{
+		CallsStarted:             s.callsStarted,
+		CallsSucceeded:           s.callsSucceeded,
+		CallsFailed:              s.callsFailed,
+		LastCallStartedTimestamp: s.lastCallStartedTime,
 	}
-	hdr, data, err := encode(s.opts.codec, msg, cp, cbuf, outPayload)
+}
+
+func (s *Server) incrCallsStarted() {
+	s.czmu.Lock()
+	s.callsStarted++
+	s.lastCallStartedTime = time.Now()
+	s.czmu.Unlock()
+}
+
+func (s *Server) incrCallsSucceeded() {
+	s.czmu.Lock()
+	s.callsSucceeded++
+	s.czmu.Unlock()
+}
+
+func (s *Server) incrCallsFailed() {
+	s.czmu.Lock()
+	s.callsFailed++
+	s.czmu.Unlock()
+}
+
+func (s *Server) sendResponse(t transport.ServerTransport, stream *transport.Stream, msg interface{}, cp Compressor, opts *transport.Options, comp encoding.Compressor) error {
+	data, err := encode(s.getCodec(stream.ContentSubtype()), msg)
 	if err != nil {
 		grpclog.Errorln("grpc: server failed to encode response: ", err)
 		return err
 	}
-	if len(data) > s.opts.maxSendMessageSize {
-		return status.Errorf(codes.ResourceExhausted, "grpc: trying to send message larger than max (%d vs. %d)", len(data), s.opts.maxSendMessageSize)
+	compData, err := compress(data, cp, comp)
+	if err != nil {
+		grpclog.Errorln("grpc: server failed to compress response: ", err)
+		return err
 	}
-	err = t.Write(stream, hdr, data, opts)
-	if err == nil && outPayload != nil {
-		outPayload.SentTime = time.Now()
-		s.opts.statsHandler.HandleRPC(stream.Context(), outPayload)
+	hdr, payload := msgHeader(data, compData)
+	// TODO(dfawley): should we be checking len(data) instead?
+	if len(payload) > s.opts.maxSendMessageSize {
+		return status.Errorf(codes.ResourceExhausted, "grpc: trying to send message larger than max (%d vs. %d)", len(payload), s.opts.maxSendMessageSize)
+	}
+	err = t.Write(stream, hdr, payload, opts)
+	if err == nil && s.opts.statsHandler != nil {
+		s.opts.statsHandler.HandleRPC(stream.Context(), outPayload(false, msg, data, payload, time.Now()))
 	}
 	return err
 }
 
 func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.Stream, srv *service, md *MethodDesc, trInfo *traceInfo) (err error) {
+	if channelz.IsOn() {
+		s.incrCallsStarted()
+		defer func() {
+			if err != nil && err != io.EOF {
+				s.incrCallsFailed()
+			} else {
+				s.incrCallsSucceeded()
+			}
+		}()
+	}
 	sh := s.opts.statsHandler
 	if sh != nil {
+		beginTime := time.Now()
 		begin := &stats.Begin{
-			BeginTime: time.Now(),
+			BeginTime: beginTime,
 		}
 		sh.HandleRPC(stream.Context(), begin)
 		defer func() {
 			end := &stats.End{
-				EndTime: time.Now(),
+				BeginTime: beginTime,
+				EndTime:   time.Now(),
 			}
 			if err != nil && err != io.EOF {
 				end.Error = toRPCErr(err)
@@ -741,10 +889,43 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 			}
 		}()
 	}
+
+	// comp and cp are used for compression.  decomp and dc are used for
+	// decompression.  If comp and decomp are both set, they are the same;
+	// however they are kept separate to ensure that at most one of the
+	// compressor/decompressor variable pairs are set for use later.
+	var comp, decomp encoding.Compressor
+	var cp Compressor
+	var dc Decompressor
+
+	// If dc is set and matches the stream's compression, use it.  Otherwise, try
+	// to find a matching registered compressor for decomp.
+	if rc := stream.RecvCompress(); s.opts.dc != nil && s.opts.dc.Type() == rc {
+		dc = s.opts.dc
+	} else if rc != "" && rc != encoding.Identity {
+		decomp = encoding.GetCompressor(rc)
+		if decomp == nil {
+			st := status.Newf(codes.Unimplemented, "grpc: Decompressor is not installed for grpc-encoding %q", rc)
+			t.WriteStatus(stream, st)
+			return st.Err()
+		}
+	}
+
+	// If cp is set, use it.  Otherwise, attempt to compress the response using
+	// the incoming message compression method.
+	//
+	// NOTE: this needs to be ahead of all handling, https://github.com/grpc/grpc-go/issues/686.
 	if s.opts.cp != nil {
-		// NOTE: this needs to be ahead of all handling, https://github.com/grpc/grpc-go/issues/686.
-		stream.SetSendCompress(s.opts.cp.Type())
+		cp = s.opts.cp
+		stream.SetSendCompress(cp.Type())
+	} else if rc := stream.RecvCompress(); rc != "" && rc != encoding.Identity {
+		// Legacy compressor not specified; attempt to respond with same encoding.
+		comp = encoding.GetCompressor(rc)
+		if comp != nil {
+			stream.SetSendCompress(rc)
+		}
 	}
+
 	p := &parser{r: stream}
 	pf, req, err := p.recvMsg(s.opts.maxReceiveMessageSize)
 	if err == io.EOF {
@@ -752,7 +933,7 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 		return err
 	}
 	if err == io.ErrUnexpectedEOF {
-		err = Errorf(codes.Internal, io.ErrUnexpectedEOF.Error())
+		err = status.Errorf(codes.Internal, io.ErrUnexpectedEOF.Error())
 	}
 	if err != nil {
 		if st, ok := status.FromError(err); ok {
@@ -773,19 +954,14 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 		}
 		return err
 	}
-
-	if err := checkRecvPayload(pf, stream.RecvCompress(), s.opts.dc); err != nil {
-		if st, ok := status.FromError(err); ok {
-			if e := t.WriteStatus(stream, st); e != nil {
-				grpclog.Warningf("grpc: Server.processUnaryRPC failed to write status %v", e)
-			}
-			return err
-		}
-		if e := t.WriteStatus(stream, status.New(codes.Internal, err.Error())); e != nil {
+	if channelz.IsOn() {
+		t.IncrMsgRecv()
+	}
+	if st := checkRecvPayload(pf, stream.RecvCompress(), dc != nil || decomp != nil); st != nil {
+		if e := t.WriteStatus(stream, st); e != nil {
 			grpclog.Warningf("grpc: Server.processUnaryRPC failed to write status %v", e)
 		}
-
-		// TODO checkRecvPayload always return RPC error. Add a return here if necessary.
+		return st.Err()
 	}
 	var inPayload *stats.InPayload
 	if sh != nil {
@@ -799,9 +975,17 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 		}
 		if pf == compressionMade {
 			var err error
-			req, err = s.opts.dc.Do(bytes.NewReader(req))
-			if err != nil {
-				return Errorf(codes.Internal, err.Error())
+			if dc != nil {
+				req, err = dc.Do(bytes.NewReader(req))
+				if err != nil {
+					return status.Errorf(codes.Internal, err.Error())
+				}
+			} else {
+				tmp, _ := decomp.Decompress(bytes.NewReader(req))
+				req, err = ioutil.ReadAll(tmp)
+				if err != nil {
+					return status.Errorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
+				}
 			}
 		}
 		if len(req) > s.opts.maxReceiveMessageSize {
@@ -809,7 +993,7 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 			// java implementation.
 			return status.Errorf(codes.ResourceExhausted, "grpc: received message larger than max (%d vs. %d)", len(req), s.opts.maxReceiveMessageSize)
 		}
-		if err := s.opts.codec.Unmarshal(req, v); err != nil {
+		if err := s.getCodec(stream.ContentSubtype()).Unmarshal(req, v); err != nil {
 			return status.Errorf(codes.Internal, "grpc: error unmarshalling request: %v", err)
 		}
 		if inPayload != nil {
@@ -823,12 +1007,13 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 		}
 		return nil
 	}
-	reply, appErr := md.Handler(srv.server, stream.Context(), df, s.opts.unaryInt)
+	ctx := NewContextWithServerTransportStream(stream.Context(), stream)
+	reply, appErr := md.Handler(srv.server, ctx, df, s.opts.unaryInt)
 	if appErr != nil {
 		appStatus, ok := status.FromError(appErr)
 		if !ok {
 			// Convert appErr if it is not a grpc status error.
-			appErr = status.Error(convertCode(appErr), appErr.Error())
+			appErr = status.Error(codes.Unknown, appErr.Error())
 			appStatus, _ = status.FromError(appErr)
 		}
 		if trInfo != nil {
@@ -847,7 +1032,8 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 		Last:  true,
 		Delay: false,
 	}
-	if err := s.sendResponse(t, stream, reply, s.opts.cp, opts); err != nil {
+
+	if err := s.sendResponse(t, stream, reply, cp, opts, comp); err != nil {
 		if err == io.EOF {
 			// The entire stream is done (for unary RPC only).
 			return err
@@ -870,6 +1056,9 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 		}
 		return err
 	}
+	if channelz.IsOn() {
+		t.IncrMsgSent()
+	}
 	if trInfo != nil {
 		trInfo.tr.LazyLog(&payload{sent: true, msg: reply}, true)
 	}
@@ -880,15 +1069,27 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 }
 
 func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transport.Stream, srv *service, sd *StreamDesc, trInfo *traceInfo) (err error) {
+	if channelz.IsOn() {
+		s.incrCallsStarted()
+		defer func() {
+			if err != nil && err != io.EOF {
+				s.incrCallsFailed()
+			} else {
+				s.incrCallsSucceeded()
+			}
+		}()
+	}
 	sh := s.opts.statsHandler
 	if sh != nil {
+		beginTime := time.Now()
 		begin := &stats.Begin{
-			BeginTime: time.Now(),
+			BeginTime: beginTime,
 		}
 		sh.HandleRPC(stream.Context(), begin)
 		defer func() {
 			end := &stats.End{
-				EndTime: time.Now(),
+				BeginTime: beginTime,
+				EndTime:   time.Now(),
 			}
 			if err != nil && err != io.EOF {
 				end.Error = toRPCErr(err)
@@ -896,21 +1097,47 @@ func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transp
 			sh.HandleRPC(stream.Context(), end)
 		}()
 	}
-	if s.opts.cp != nil {
-		stream.SetSendCompress(s.opts.cp.Type())
-	}
+	ctx := NewContextWithServerTransportStream(stream.Context(), stream)
 	ss := &serverStream{
+		ctx:   ctx,
 		t:     t,
 		s:     stream,
 		p:     &parser{r: stream},
-		codec: s.opts.codec,
-		cp:    s.opts.cp,
-		dc:    s.opts.dc,
+		codec: s.getCodec(stream.ContentSubtype()),
 		maxReceiveMessageSize: s.opts.maxReceiveMessageSize,
 		maxSendMessageSize:    s.opts.maxSendMessageSize,
 		trInfo:                trInfo,
 		statsHandler:          sh,
 	}
+
+	// If dc is set and matches the stream's compression, use it.  Otherwise, try
+	// to find a matching registered compressor for decomp.
+	if rc := stream.RecvCompress(); s.opts.dc != nil && s.opts.dc.Type() == rc {
+		ss.dc = s.opts.dc
+	} else if rc != "" && rc != encoding.Identity {
+		ss.decomp = encoding.GetCompressor(rc)
+		if ss.decomp == nil {
+			st := status.Newf(codes.Unimplemented, "grpc: Decompressor is not installed for grpc-encoding %q", rc)
+			t.WriteStatus(ss.s, st)
+			return st.Err()
+		}
+	}
+
+	// If cp is set, use it.  Otherwise, attempt to compress the response using
+	// the incoming message compression method.
+	//
+	// NOTE: this needs to be ahead of all handling, https://github.com/grpc/grpc-go/issues/686.
+	if s.opts.cp != nil {
+		ss.cp = s.opts.cp
+		stream.SetSendCompress(s.opts.cp.Type())
+	} else if rc := stream.RecvCompress(); rc != "" && rc != encoding.Identity {
+		// Legacy compressor not specified; attempt to respond with same encoding.
+		ss.comp = encoding.GetCompressor(rc)
+		if ss.comp != nil {
+			stream.SetSendCompress(rc)
+		}
+	}
+
 	if trInfo != nil {
 		trInfo.tr.LazyLog(&trInfo.firstLine, false)
 		defer func() {
@@ -946,7 +1173,7 @@ func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transp
 			case transport.StreamError:
 				appStatus = status.New(err.Code, err.Desc)
 			default:
-				appStatus = status.New(convertCode(appErr), appErr.Error())
+				appStatus = status.New(codes.Unknown, appErr.Error())
 			}
 			appErr = appStatus.Err()
 		}
@@ -966,7 +1193,6 @@ func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transp
 		ss.mu.Unlock()
 	}
 	return t.WriteStatus(ss.s, status.New(codes.OK, ""))
-
 }
 
 func (s *Server) handleStream(t transport.ServerTransport, stream *transport.Stream, trInfo *traceInfo) {
@@ -1048,12 +1274,65 @@ func (s *Server) handleStream(t transport.ServerTransport, stream *transport.Str
 	}
 }
 
+// The key to save ServerTransportStream in the context.
+type streamKey struct{}
+
+// NewContextWithServerTransportStream creates a new context from ctx and
+// attaches stream to it.
+//
+// This API is EXPERIMENTAL.
+func NewContextWithServerTransportStream(ctx context.Context, stream ServerTransportStream) context.Context {
+	return context.WithValue(ctx, streamKey{}, stream)
+}
+
+// ServerTransportStream is a minimal interface that a transport stream must
+// implement. This can be used to mock an actual transport stream for tests of
+// handler code that use, for example, grpc.SetHeader (which requires some
+// stream to be in context).
+//
+// See also NewContextWithServerTransportStream.
+//
+// This API is EXPERIMENTAL.
+type ServerTransportStream interface {
+	Method() string
+	SetHeader(md metadata.MD) error
+	SendHeader(md metadata.MD) error
+	SetTrailer(md metadata.MD) error
+}
+
+// ServerTransportStreamFromContext returns the ServerTransportStream saved in
+// ctx. Returns nil if the given context has no stream associated with it
+// (which implies it is not an RPC invocation context).
+//
+// This API is EXPERIMENTAL.
+func ServerTransportStreamFromContext(ctx context.Context) ServerTransportStream {
+	s, _ := ctx.Value(streamKey{}).(ServerTransportStream)
+	return s
+}
+
 // Stop stops the gRPC server. It immediately closes all open
 // connections and listeners.
 // It cancels all active RPCs on the server side and the corresponding
 // pending RPCs on the client side will get notified by connection
 // errors.
 func (s *Server) Stop() {
+	s.quitOnce.Do(func() {
+		close(s.quit)
+	})
+
+	defer func() {
+		s.serveWG.Wait()
+		s.doneOnce.Do(func() {
+			close(s.done)
+		})
+	}()
+
+	s.channelzRemoveOnce.Do(func() {
+		if channelz.IsOn() {
+			channelz.RemoveEntry(s.channelzID)
+		}
+	})
+
 	s.mu.Lock()
 	listeners := s.lis
 	s.lis = nil
@@ -1071,7 +1350,6 @@ func (s *Server) Stop() {
 	}
 
 	s.mu.Lock()
-	s.cancel()
 	if s.events != nil {
 		s.events.Finish()
 		s.events = nil
@@ -1083,22 +1361,44 @@ func (s *Server) Stop() {
 // accepting new connections and RPCs and blocks until all the pending RPCs are
 // finished.
 func (s *Server) GracefulStop() {
+	s.quitOnce.Do(func() {
+		close(s.quit)
+	})
+
+	defer func() {
+		s.doneOnce.Do(func() {
+			close(s.done)
+		})
+	}()
+
+	s.channelzRemoveOnce.Do(func() {
+		if channelz.IsOn() {
+			channelz.RemoveEntry(s.channelzID)
+		}
+	})
 	s.mu.Lock()
-	defer s.mu.Unlock()
 	if s.conns == nil {
+		s.mu.Unlock()
 		return
 	}
+
 	for lis := range s.lis {
 		lis.Close()
 	}
 	s.lis = nil
-	s.cancel()
 	if !s.drain {
 		for c := range s.conns {
 			c.(transport.ServerTransport).Drain()
 		}
 		s.drain = true
 	}
+
+	// Wait for serving threads to be ready to exit.  Only then can we be sure no
+	// new conns will be created.
+	s.mu.Unlock()
+	s.serveWG.Wait()
+	s.mu.Lock()
+
 	for len(s.conns) != 0 {
 		s.cv.Wait()
 	}
@@ -1107,26 +1407,29 @@ func (s *Server) GracefulStop() {
 		s.events.Finish()
 		s.events = nil
 	}
+	s.mu.Unlock()
 }
 
 func init() {
-	internal.TestingCloseConns = func(arg interface{}) {
-		arg.(*Server).testingCloseConns()
-	}
 	internal.TestingUseHandlerImpl = func(arg interface{}) {
 		arg.(*Server).opts.useHandlerImpl = true
 	}
 }
 
-// testingCloseConns closes all existing transports but keeps s.lis
-// accepting new connections.
-func (s *Server) testingCloseConns() {
-	s.mu.Lock()
-	for c := range s.conns {
-		c.Close()
-		delete(s.conns, c)
+// contentSubtype must be lowercase
+// cannot return nil
+func (s *Server) getCodec(contentSubtype string) baseCodec {
+	if s.opts.codec != nil {
+		return s.opts.codec
 	}
-	s.mu.Unlock()
+	if contentSubtype == "" {
+		return encoding.GetCodec(proto.Name)
+	}
+	codec := encoding.GetCodec(contentSubtype)
+	if codec == nil {
+		return encoding.GetCodec(proto.Name)
+	}
+	return codec
 }
 
 // SetHeader sets the header metadata.
@@ -1139,9 +1442,9 @@ func SetHeader(ctx context.Context, md metadata.MD) error {
 	if md.Len() == 0 {
 		return nil
 	}
-	stream, ok := transport.StreamFromContext(ctx)
-	if !ok {
-		return Errorf(codes.Internal, "grpc: failed to fetch the stream from the context %v", ctx)
+	stream := ServerTransportStreamFromContext(ctx)
+	if stream == nil {
+		return status.Errorf(codes.Internal, "grpc: failed to fetch the stream from the context %v", ctx)
 	}
 	return stream.SetHeader(md)
 }
@@ -1149,15 +1452,11 @@ func SetHeader(ctx context.Context, md metadata.MD) error {
 // SendHeader sends header metadata. It may be called at most once.
 // The provided md and headers set by SetHeader() will be sent.
 func SendHeader(ctx context.Context, md metadata.MD) error {
-	stream, ok := transport.StreamFromContext(ctx)
-	if !ok {
-		return Errorf(codes.Internal, "grpc: failed to fetch the stream from the context %v", ctx)
+	stream := ServerTransportStreamFromContext(ctx)
+	if stream == nil {
+		return status.Errorf(codes.Internal, "grpc: failed to fetch the stream from the context %v", ctx)
 	}
-	t := stream.ServerTransport()
-	if t == nil {
-		grpclog.Fatalf("grpc: SendHeader: %v has no ServerTransport to send header metadata.", stream)
-	}
-	if err := t.WriteHeader(stream, md); err != nil {
+	if err := stream.SendHeader(md); err != nil {
 		return toRPCErr(err)
 	}
 	return nil
@@ -1169,9 +1468,19 @@ func SetTrailer(ctx context.Context, md metadata.MD) error {
 	if md.Len() == 0 {
 		return nil
 	}
-	stream, ok := transport.StreamFromContext(ctx)
-	if !ok {
-		return Errorf(codes.Internal, "grpc: failed to fetch the stream from the context %v", ctx)
+	stream := ServerTransportStreamFromContext(ctx)
+	if stream == nil {
+		return status.Errorf(codes.Internal, "grpc: failed to fetch the stream from the context %v", ctx)
 	}
 	return stream.SetTrailer(md)
 }
+
+// Method returns the method string for the server context.  The returned
+// string is in the format of "/service/method".
+func Method(ctx context.Context) (string, bool) {
+	s := ServerTransportStreamFromContext(ctx)
+	if s == nil {
+		return "", false
+	}
+	return s.Method(), true
+}
diff --git a/vendor/google.golang.org/grpc/service_config.go b/vendor/google.golang.org/grpc/service_config.go
new file mode 100644
index 0000000..015631d
--- /dev/null
+++ b/vendor/google.golang.org/grpc/service_config.go
@@ -0,0 +1,233 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+
+	"google.golang.org/grpc/grpclog"
+)
+
+const maxInt = int(^uint(0) >> 1)
+
+// MethodConfig defines the configuration recommended by the service providers for a
+// particular method.
+//
+// Deprecated: Users should not use this struct. Service config should be received
+// through name resolver, as specified here
+// https://github.com/grpc/grpc/blob/master/doc/service_config.md
+type MethodConfig struct {
+	// WaitForReady indicates whether RPCs sent to this method should wait until
+	// the connection is ready by default (!failfast). The value specified via the
+	// gRPC client API will override the value set here.
+	WaitForReady *bool
+	// Timeout is the default timeout for RPCs sent to this method. The actual
+	// deadline used will be the minimum of the value specified here and the value
+	// set by the application via the gRPC client API.  If either one is not set,
+	// then the other will be used.  If neither is set, then the RPC has no deadline.
+	Timeout *time.Duration
+	// MaxReqSize is the maximum allowed payload size for an individual request in a
+	// stream (client->server) in bytes. The size which is measured is the serialized
+	// payload after per-message compression (but before stream compression) in bytes.
+	// The actual value used is the minimum of the value specified here and the value set
+	// by the application via the gRPC client API. If either one is not set, then the other
+	// will be used.  If neither is set, then the built-in default is used.
+	MaxReqSize *int
+	// MaxRespSize is the maximum allowed payload size for an individual response in a
+	// stream (server->client) in bytes.
+	MaxRespSize *int
+}
+
+// ServiceConfig is provided by the service provider and contains parameters for how
+// clients that connect to the service should behave.
+//
+// Deprecated: Users should not use this struct. Service config should be received
+// through name resolver, as specified here
+// https://github.com/grpc/grpc/blob/master/doc/service_config.md
+type ServiceConfig struct {
+	// LB is the load balancer the service providers recommends. The balancer specified
+	// via grpc.WithBalancer will override this.
+	LB *string
+	// Methods contains a map for the methods in this service.
+	// If there is an exact match for a method (i.e. /service/method) in the map, use the corresponding MethodConfig.
+	// If there's no exact match, look for the default config for the service (/service/) and use the corresponding MethodConfig if it exists.
+	// Otherwise, the method has no MethodConfig to use.
+	Methods map[string]MethodConfig
+
+	stickinessMetadataKey *string
+}
+
+func parseDuration(s *string) (*time.Duration, error) {
+	if s == nil {
+		return nil, nil
+	}
+	if !strings.HasSuffix(*s, "s") {
+		return nil, fmt.Errorf("malformed duration %q", *s)
+	}
+	ss := strings.SplitN((*s)[:len(*s)-1], ".", 3)
+	if len(ss) > 2 {
+		return nil, fmt.Errorf("malformed duration %q", *s)
+	}
+	// hasDigits is set if either the whole or fractional part of the number is
+	// present, since both are optional but one is required.
+	hasDigits := false
+	var d time.Duration
+	if len(ss[0]) > 0 {
+		i, err := strconv.ParseInt(ss[0], 10, 32)
+		if err != nil {
+			return nil, fmt.Errorf("malformed duration %q: %v", *s, err)
+		}
+		d = time.Duration(i) * time.Second
+		hasDigits = true
+	}
+	if len(ss) == 2 && len(ss[1]) > 0 {
+		if len(ss[1]) > 9 {
+			return nil, fmt.Errorf("malformed duration %q", *s)
+		}
+		f, err := strconv.ParseInt(ss[1], 10, 64)
+		if err != nil {
+			return nil, fmt.Errorf("malformed duration %q: %v", *s, err)
+		}
+		for i := 9; i > len(ss[1]); i-- {
+			f *= 10
+		}
+		d += time.Duration(f)
+		hasDigits = true
+	}
+	if !hasDigits {
+		return nil, fmt.Errorf("malformed duration %q", *s)
+	}
+
+	return &d, nil
+}
+
+type jsonName struct {
+	Service *string
+	Method  *string
+}
+
+func (j jsonName) generatePath() (string, bool) {
+	if j.Service == nil {
+		return "", false
+	}
+	res := "/" + *j.Service + "/"
+	if j.Method != nil {
+		res += *j.Method
+	}
+	return res, true
+}
+
+// TODO(lyuxuan): delete this struct after cleaning up old service config implementation.
+type jsonMC struct {
+	Name                    *[]jsonName
+	WaitForReady            *bool
+	Timeout                 *string
+	MaxRequestMessageBytes  *int64
+	MaxResponseMessageBytes *int64
+}
+
+// TODO(lyuxuan): delete this struct after cleaning up old service config implementation.
+type jsonSC struct {
+	LoadBalancingPolicy   *string
+	StickinessMetadataKey *string
+	MethodConfig          *[]jsonMC
+}
+
+func parseServiceConfig(js string) (ServiceConfig, error) {
+	var rsc jsonSC
+	err := json.Unmarshal([]byte(js), &rsc)
+	if err != nil {
+		grpclog.Warningf("grpc: parseServiceConfig error unmarshaling %s due to %v", js, err)
+		return ServiceConfig{}, err
+	}
+	sc := ServiceConfig{
+		LB:      rsc.LoadBalancingPolicy,
+		Methods: make(map[string]MethodConfig),
+
+		stickinessMetadataKey: rsc.StickinessMetadataKey,
+	}
+	if rsc.MethodConfig == nil {
+		return sc, nil
+	}
+
+	for _, m := range *rsc.MethodConfig {
+		if m.Name == nil {
+			continue
+		}
+		d, err := parseDuration(m.Timeout)
+		if err != nil {
+			grpclog.Warningf("grpc: parseServiceConfig error unmarshaling %s due to %v", js, err)
+			return ServiceConfig{}, err
+		}
+
+		mc := MethodConfig{
+			WaitForReady: m.WaitForReady,
+			Timeout:      d,
+		}
+		if m.MaxRequestMessageBytes != nil {
+			if *m.MaxRequestMessageBytes > int64(maxInt) {
+				mc.MaxReqSize = newInt(maxInt)
+			} else {
+				mc.MaxReqSize = newInt(int(*m.MaxRequestMessageBytes))
+			}
+		}
+		if m.MaxResponseMessageBytes != nil {
+			if *m.MaxResponseMessageBytes > int64(maxInt) {
+				mc.MaxRespSize = newInt(maxInt)
+			} else {
+				mc.MaxRespSize = newInt(int(*m.MaxResponseMessageBytes))
+			}
+		}
+		for _, n := range *m.Name {
+			if path, valid := n.generatePath(); valid {
+				sc.Methods[path] = mc
+			}
+		}
+	}
+
+	return sc, nil
+}
+
+func min(a, b *int) *int {
+	if *a < *b {
+		return a
+	}
+	return b
+}
+
+func getMaxSize(mcMax, doptMax *int, defaultVal int) *int {
+	if mcMax == nil && doptMax == nil {
+		return &defaultVal
+	}
+	if mcMax != nil && doptMax != nil {
+		return min(mcMax, doptMax)
+	}
+	if mcMax != nil {
+		return mcMax
+	}
+	return doptMax
+}
+
+func newInt(b int) *int {
+	return &b
+}
diff --git a/vendor/google.golang.org/grpc/stats/stats.go b/vendor/google.golang.org/grpc/stats/stats.go
index d5aa2f7..3f13190 100644
--- a/vendor/google.golang.org/grpc/stats/stats.go
+++ b/vendor/google.golang.org/grpc/stats/stats.go
@@ -169,6 +169,8 @@ func (s *OutTrailer) isRPCStats() {}
 type End struct {
 	// Client is true if this End is from client side.
 	Client bool
+	// BeginTime is the time when the RPC began.
+	BeginTime time.Time
 	// EndTime is the time when the RPC ends.
 	EndTime time.Time
 	// Error is the error the RPC ended with. It is an error generated from
diff --git a/vendor/google.golang.org/grpc/status/go16.go b/vendor/google.golang.org/grpc/status/go16.go
new file mode 100644
index 0000000..e59b53e
--- /dev/null
+++ b/vendor/google.golang.org/grpc/status/go16.go
@@ -0,0 +1,42 @@
+// +build go1.6,!go1.7
+
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package status
+
+import (
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+)
+
+// FromContextError converts a context error into a Status.  It returns a
+// Status with codes.OK if err is nil, or a Status with codes.Unknown if err is
+// non-nil and not a context error.
+func FromContextError(err error) *Status {
+	switch err {
+	case nil:
+		return New(codes.OK, "")
+	case context.DeadlineExceeded:
+		return New(codes.DeadlineExceeded, err.Error())
+	case context.Canceled:
+		return New(codes.Canceled, err.Error())
+	default:
+		return New(codes.Unknown, err.Error())
+	}
+}
diff --git a/vendor/google.golang.org/grpc/status/go17.go b/vendor/google.golang.org/grpc/status/go17.go
new file mode 100644
index 0000000..0902151
--- /dev/null
+++ b/vendor/google.golang.org/grpc/status/go17.go
@@ -0,0 +1,44 @@
+// +build go1.7
+
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package status
+
+import (
+	"context"
+
+	netctx "golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+)
+
+// FromContextError converts a context error into a Status.  It returns a
+// Status with codes.OK if err is nil, or a Status with codes.Unknown if err is
+// non-nil and not a context error.
+func FromContextError(err error) *Status {
+	switch err {
+	case nil:
+		return New(codes.OK, "")
+	case context.DeadlineExceeded, netctx.DeadlineExceeded:
+		return New(codes.DeadlineExceeded, err.Error())
+	case context.Canceled, netctx.Canceled:
+		return New(codes.Canceled, err.Error())
+	default:
+		return New(codes.Unknown, err.Error())
+	}
+}
diff --git a/vendor/google.golang.org/grpc/status/status.go b/vendor/google.golang.org/grpc/status/status.go
index 871dc4b..9c61b09 100644
--- a/vendor/google.golang.org/grpc/status/status.go
+++ b/vendor/google.golang.org/grpc/status/status.go
@@ -46,7 +46,7 @@ func (se *statusError) Error() string {
 	return fmt.Sprintf("rpc error: code = %s desc = %s", codes.Code(p.GetCode()), p.GetMessage())
 }
 
-func (se *statusError) status() *Status {
+func (se *statusError) GRPCStatus() *Status {
 	return &Status{s: (*spb.Status)(se)}
 }
 
@@ -120,15 +120,23 @@ func FromProto(s *spb.Status) *Status {
 }
 
 // FromError returns a Status representing err if it was produced from this
-// package, otherwise it returns nil, false.
+// package or has a method `GRPCStatus() *Status`. Otherwise, ok is false and a
+// Status is returned with codes.Unknown and the original error message.
 func FromError(err error) (s *Status, ok bool) {
 	if err == nil {
 		return &Status{s: &spb.Status{Code: int32(codes.OK)}}, true
 	}
-	if s, ok := err.(*statusError); ok {
-		return s.status(), true
+	if se, ok := err.(interface{ GRPCStatus() *Status }); ok {
+		return se.GRPCStatus(), true
 	}
-	return nil, false
+	return New(codes.Unknown, err.Error()), false
+}
+
+// Convert is a convenience function which removes the need to handle the
+// boolean return value from FromError.
+func Convert(err error) *Status {
+	s, _ := FromError(err)
+	return s
 }
 
 // WithDetails returns a new status with the provided details messages appended to the status.
@@ -166,3 +174,16 @@ func (s *Status) Details() []interface{} {
 	}
 	return details
 }
+
+// Code returns the Code of the error if it is a Status error, codes.OK if err
+// is nil, or codes.Unknown otherwise.
+func Code(err error) codes.Code {
+	// Don't use FromError to avoid allocation of OK status.
+	if err == nil {
+		return codes.OK
+	}
+	if se, ok := err.(interface{ GRPCStatus() *Status }); ok {
+		return se.GRPCStatus().Code()
+	}
+	return codes.Unknown
+}
diff --git a/vendor/google.golang.org/grpc/stickiness_linkedmap.go b/vendor/google.golang.org/grpc/stickiness_linkedmap.go
new file mode 100644
index 0000000..1c726af
--- /dev/null
+++ b/vendor/google.golang.org/grpc/stickiness_linkedmap.go
@@ -0,0 +1,97 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"container/list"
+)
+
+type linkedMapKVPair struct {
+	key   string
+	value *stickyStoreEntry
+}
+
+// linkedMap is an implementation of a map that supports removing the oldest
+// entry.
+//
+// linkedMap is NOT thread safe.
+//
+// It's for use of stickiness only!
+type linkedMap struct {
+	m map[string]*list.Element
+	l *list.List // Head of the list is the oldest element.
+}
+
+// newLinkedMap returns a new LinkedMap.
+func newLinkedMap() *linkedMap {
+	return &linkedMap{
+		m: make(map[string]*list.Element),
+		l: list.New(),
+	}
+}
+
+// put adds entry (key, value) to the map. Existing key will be overridden.
+func (m *linkedMap) put(key string, value *stickyStoreEntry) {
+	if oldE, ok := m.m[key]; ok {
+		// Remove existing entry.
+		m.l.Remove(oldE)
+	}
+	e := m.l.PushBack(&linkedMapKVPair{key: key, value: value})
+	m.m[key] = e
+}
+
+// get returns the value of the given key.
+func (m *linkedMap) get(key string) (*stickyStoreEntry, bool) {
+	e, ok := m.m[key]
+	if !ok {
+		return nil, false
+	}
+	m.l.MoveToBack(e)
+	return e.Value.(*linkedMapKVPair).value, true
+}
+
+// remove removes key from the map, and returns the value. The map is not
+// modified if key is not in the map.
+func (m *linkedMap) remove(key string) (*stickyStoreEntry, bool) {
+	e, ok := m.m[key]
+	if !ok {
+		return nil, false
+	}
+	delete(m.m, key)
+	m.l.Remove(e)
+	return e.Value.(*linkedMapKVPair).value, true
+}
+
+// len returns the len of the map.
+func (m *linkedMap) len() int {
+	return len(m.m)
+}
+
+// clear removes all elements from the map.
+func (m *linkedMap) clear() {
+	m.m = make(map[string]*list.Element)
+	m.l = list.New()
+}
+
+// removeOldest removes the oldest key from the map.
+func (m *linkedMap) removeOldest() {
+	e := m.l.Front()
+	m.l.Remove(e)
+	delete(m.m, e.Value.(*linkedMapKVPair).key)
+}
diff --git a/vendor/google.golang.org/grpc/stream.go b/vendor/google.golang.org/grpc/stream.go
index 75eab40..152d9ec 100644
--- a/vendor/google.golang.org/grpc/stream.go
+++ b/vendor/google.golang.org/grpc/stream.go
@@ -19,7 +19,6 @@
 package grpc
 
 import (
-	"bytes"
 	"errors"
 	"io"
 	"sync"
@@ -29,15 +28,19 @@ import (
 	"golang.org/x/net/trace"
 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/metadata"
-	"google.golang.org/grpc/peer"
 	"google.golang.org/grpc/stats"
 	"google.golang.org/grpc/status"
 	"google.golang.org/grpc/transport"
 )
 
 // StreamHandler defines the handler called by gRPC server to complete the
-// execution of a streaming RPC.
+// execution of a streaming RPC. If a StreamHandler returns an error, it
+// should be produced by the status package, or else gRPC will use
+// codes.Unknown as the status code and err.Error() as the status message
+// of the RPC.
 type StreamHandler func(srv interface{}, stream ServerStream) error
 
 // StreamDesc represents a streaming RPC service's method specification.
@@ -51,6 +54,8 @@ type StreamDesc struct {
 }
 
 // Stream defines the common interface a client or server stream has to satisfy.
+//
+// All errors returned from Stream are compatible with the status package.
 type Stream interface {
 	// Context returns the context for this stream.
 	Context() context.Context
@@ -89,43 +94,78 @@ type ClientStream interface {
 	// Stream.SendMsg() may return a non-nil error when something wrong happens sending
 	// the request. The returned error indicates the status of this sending, not the final
 	// status of the RPC.
-	// Always call Stream.RecvMsg() to get the final status if you care about the status of
-	// the RPC.
+	//
+	// Always call Stream.RecvMsg() to drain the stream and get the final
+	// status, otherwise there could be leaked resources.
 	Stream
 }
 
-// NewClientStream creates a new Stream for the client side. This is called
-// by generated code.
-func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (_ ClientStream, err error) {
+// NewStream creates a new Stream for the client side. This is typically
+// called by generated code. ctx is used for the lifetime of the stream.
+//
+// To ensure resources are not leaked due to the stream returned, one of the following
+// actions must be performed:
+//
+//      1. Call Close on the ClientConn.
+//      2. Cancel the context provided.
+//      3. Call RecvMsg until a non-nil error is returned. A protobuf-generated
+//         client-streaming RPC, for instance, might use the helper function
+//         CloseAndRecv (note that CloseSend does not Recv, therefore is not
+//         guaranteed to release all resources).
+//      4. Receive a non-nil, non-io.EOF error from Header or SendMsg.
+//
+// If none of the above happen, a goroutine and a context will be leaked, and grpc
+// will not call the optionally-configured stats handler with a stats.End message.
+func (cc *ClientConn) NewStream(ctx context.Context, desc *StreamDesc, method string, opts ...CallOption) (ClientStream, error) {
+	// allow interceptor to see all applicable call options, which means those
+	// configured as defaults from dial option as well as per-call options
+	opts = combine(cc.dopts.callOptions, opts)
+
 	if cc.dopts.streamInt != nil {
 		return cc.dopts.streamInt(ctx, desc, cc, method, newClientStream, opts...)
 	}
 	return newClientStream(ctx, desc, cc, method, opts...)
 }
 
+// NewClientStream is a wrapper for ClientConn.NewStream.
+//
+// DEPRECATED: Use ClientConn.NewStream instead.
+func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) {
+	return cc.NewStream(ctx, desc, method, opts...)
+}
+
 func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (_ ClientStream, err error) {
-	var (
-		t      transport.ClientTransport
-		s      *transport.Stream
-		done   func(balancer.DoneInfo)
-		cancel context.CancelFunc
-	)
+	if channelz.IsOn() {
+		cc.incrCallsStarted()
+		defer func() {
+			if err != nil {
+				cc.incrCallsFailed()
+			}
+		}()
+	}
 	c := defaultCallInfo()
 	mc := cc.GetMethodConfig(method)
 	if mc.WaitForReady != nil {
 		c.failFast = !*mc.WaitForReady
 	}
 
-	if mc.Timeout != nil {
+	// Possible context leak:
+	// The cancel function for the child context we create will only be called
+	// when RecvMsg returns a non-nil error, if the ClientConn is closed, or if
+	// an error is generated by SendMsg.
+	// https://github.com/grpc/grpc-go/issues/1818.
+	var cancel context.CancelFunc
+	if mc.Timeout != nil && *mc.Timeout >= 0 {
 		ctx, cancel = context.WithTimeout(ctx, *mc.Timeout)
-		defer func() {
-			if err != nil {
-				cancel()
-			}
-		}()
+	} else {
+		ctx, cancel = context.WithCancel(ctx)
 	}
+	defer func() {
+		if err != nil {
+			cancel()
+		}
+	}()
 
-	opts = append(cc.dopts.callOptions, opts...)
 	for _, o := range opts {
 		if err := o.before(c); err != nil {
 			return nil, toRPCErr(err)
@@ -133,6 +173,9 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 	}
 	c.maxSendMessageSize = getMaxSize(mc.MaxReqSize, c.maxSendMessageSize, defaultClientMaxSendMessageSize)
 	c.maxReceiveMessageSize = getMaxSize(mc.MaxRespSize, c.maxReceiveMessageSize, defaultClientMaxReceiveMessageSize)
+	if err := setCallInfoCodec(c); err != nil {
+		return nil, err
+	}
 
 	callHdr := &transport.CallHdr{
 		Host:   cc.authority,
@@ -141,10 +184,27 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 		// so we don't flush the header.
 		// If it's client streaming, the user may never send a request or send it any
 		// time soon, so we ask the transport to flush the header.
-		Flush: desc.ClientStreams,
-	}
-	if cc.dopts.cp != nil {
+		Flush:          desc.ClientStreams,
+		ContentSubtype: c.contentSubtype,
+	}
+
+	// Set our outgoing compression according to the UseCompressor CallOption, if
+	// set.  In that case, also find the compressor from the encoding package.
+	// Otherwise, use the compressor configured by the WithCompressor DialOption,
+	// if set.
+	var cp Compressor
+	var comp encoding.Compressor
+	if ct := c.compressorType; ct != "" {
+		callHdr.SendCompress = ct
+		if ct != encoding.Identity {
+			comp = encoding.GetCompressor(ct)
+			if comp == nil {
+				return nil, status.Errorf(codes.Internal, "grpc: Compressor is not installed for requested grpc-encoding %q", ct)
+			}
+		}
+	} else if cc.dopts.cp != nil {
 		callHdr.SendCompress = cc.dopts.cp.Type()
+		cp = cc.dopts.cp
 	}
 	if c.creds != nil {
 		callHdr.Creds = c.creds
@@ -170,11 +230,13 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 	}
 	ctx = newContextWithRPCInfo(ctx, c.failFast)
 	sh := cc.dopts.copts.StatsHandler
+	var beginTime time.Time
 	if sh != nil {
 		ctx = sh.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method, FailFast: c.failFast})
+		beginTime = time.Now()
 		begin := &stats.Begin{
 			Client:    true,
-			BeginTime: time.Now(),
+			BeginTime: beginTime,
 			FailFast:  c.failFast,
 		}
 		sh.HandleRPC(ctx, begin)
@@ -182,341 +244,384 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 			if err != nil {
 				// Only handle end stats if err != nil.
 				end := &stats.End{
-					Client: true,
-					Error:  err,
+					Client:    true,
+					Error:     err,
+					BeginTime: beginTime,
+					EndTime:   time.Now(),
 				}
 				sh.HandleRPC(ctx, end)
 			}
 		}()
 	}
+
+	var (
+		t    transport.ClientTransport
+		s    *transport.Stream
+		done func(balancer.DoneInfo)
+	)
 	for {
+		// Check to make sure the context has expired.  This will prevent us from
+		// looping forever if an error occurs for wait-for-ready RPCs where no data
+		// is sent on the wire.
+		select {
+		case <-ctx.Done():
+			return nil, toRPCErr(ctx.Err())
+		default:
+		}
+
 		t, done, err = cc.getTransport(ctx, c.failFast)
 		if err != nil {
-			// TODO(zhaoq): Probably revisit the error handling.
-			if _, ok := status.FromError(err); ok {
-				return nil, err
-			}
-			if err == errConnClosing || err == errConnUnavailable {
-				if c.failFast {
-					return nil, Errorf(codes.Unavailable, "%v", err)
-				}
-				continue
-			}
-			// All the other errors are treated as Internal errors.
-			return nil, Errorf(codes.Internal, "%v", err)
+			return nil, err
 		}
 
 		s, err = t.NewStream(ctx, callHdr)
 		if err != nil {
-			if _, ok := err.(transport.ConnectionError); ok && done != nil {
-				// If error is connection error, transport was sending data on wire,
-				// and we are not sure if anything has been sent on wire.
-				// If error is not connection error, we are sure nothing has been sent.
-				updateRPCInfoInContext(ctx, rpcInfo{bytesSent: true, bytesReceived: false})
-			}
 			if done != nil {
 				done(balancer.DoneInfo{Err: err})
 				done = nil
 			}
-			if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
+			// In the event of any error from NewStream, we never attempted to write
+			// anything to the wire, so we can retry indefinitely for non-fail-fast
+			// RPCs.
+			if !c.failFast {
 				continue
 			}
 			return nil, toRPCErr(err)
 		}
 		break
 	}
-	// Set callInfo.peer object from stream's context.
-	if peer, ok := peer.FromContext(s.Context()); ok {
-		c.peer = peer
-	}
+
 	cs := &clientStream{
 		opts:   opts,
 		c:      c,
+		cc:     cc,
 		desc:   desc,
-		codec:  cc.dopts.codec,
-		cp:     cc.dopts.cp,
-		dc:     cc.dopts.dc,
+		codec:  c.codec,
+		cp:     cp,
+		comp:   comp,
 		cancel: cancel,
-
-		done: done,
-		t:    t,
-		s:    s,
-		p:    &parser{r: s},
-
-		tracing: EnableTracing,
-		trInfo:  trInfo,
-
-		statsCtx:     ctx,
-		statsHandler: cc.dopts.copts.StatsHandler,
+		attempt: &csAttempt{
+			t:            t,
+			s:            s,
+			p:            &parser{r: s},
+			done:         done,
+			dc:           cc.dopts.dc,
+			ctx:          ctx,
+			trInfo:       trInfo,
+			statsHandler: sh,
+			beginTime:    beginTime,
+		},
+	}
+	cs.c.stream = cs
+	cs.attempt.cs = cs
+	if desc != unaryStreamDesc {
+		// Listen on cc and stream contexts to cleanup when the user closes the
+		// ClientConn or cancels the stream context.  In all other cases, an error
+		// should already be injected into the recv buffer by the transport, which
+		// the client will eventually receive, and then we will cancel the stream's
+		// context in clientStream.finish.
+		go func() {
+			select {
+			case <-cc.ctx.Done():
+				cs.finish(ErrClientConnClosing)
+			case <-ctx.Done():
+				cs.finish(toRPCErr(ctx.Err()))
+			}
+		}()
 	}
-	// Listen on ctx.Done() to detect cancellation and s.Done() to detect normal termination
-	// when there is no pending I/O operations on this stream.
-	go func() {
-		select {
-		case <-t.Error():
-			// Incur transport error, simply exit.
-		case <-cc.ctx.Done():
-			cs.finish(ErrClientConnClosing)
-			cs.closeTransportStream(ErrClientConnClosing)
-		case <-s.Done():
-			// TODO: The trace of the RPC is terminated here when there is no pending
-			// I/O, which is probably not the optimal solution.
-			cs.finish(s.Status().Err())
-			cs.closeTransportStream(nil)
-		case <-s.GoAway():
-			cs.finish(errConnDrain)
-			cs.closeTransportStream(errConnDrain)
-		case <-s.Context().Done():
-			err := s.Context().Err()
-			cs.finish(err)
-			cs.closeTransportStream(transport.ContextErr(err))
-		}
-	}()
 	return cs, nil
 }
 
 // clientStream implements a client side Stream.
 type clientStream struct {
-	opts   []CallOption
-	c      *callInfo
-	t      transport.ClientTransport
-	s      *transport.Stream
-	p      *parser
-	desc   *StreamDesc
-	codec  Codec
-	cp     Compressor
-	dc     Decompressor
-	cancel context.CancelFunc
+	opts []CallOption
+	c    *callInfo
+	cc   *ClientConn
+	desc *StreamDesc
 
-	tracing bool // set to EnableTracing when the clientStream is created.
+	codec baseCodec
+	cp    Compressor
+	comp  encoding.Compressor
 
-	mu       sync.Mutex
-	done     func(balancer.DoneInfo)
-	closed   bool
-	finished bool
-	// trInfo.tr is set when the clientStream is created (if EnableTracing is true),
-	// and is set to nil when the clientStream's finish method is called.
+	cancel context.CancelFunc // cancels all attempts
+
+	sentLast bool // sent an end stream
+
+	mu       sync.Mutex // guards finished
+	finished bool       // TODO: replace with atomic cmpxchg or sync.Once?
+
+	attempt *csAttempt // the active client stream attempt
+	// TODO(hedging): hedging will have multiple attempts simultaneously.
+}
+
+// csAttempt implements a single transport stream attempt within a
+// clientStream.
+type csAttempt struct {
+	cs   *clientStream
+	t    transport.ClientTransport
+	s    *transport.Stream
+	p    *parser
+	done func(balancer.DoneInfo)
+
+	dc        Decompressor
+	decomp    encoding.Compressor
+	decompSet bool
+
+	ctx context.Context // the application's context, wrapped by stats/tracing
+
+	mu sync.Mutex // guards trInfo.tr
+	// trInfo.tr is set when created (if EnableTracing is true),
+	// and cleared when the finish method is called.
 	trInfo traceInfo
 
-	// statsCtx keeps the user context for stats handling.
-	// All stats collection should use the statsCtx (instead of the stream context)
-	// so that all the generated stats for a particular RPC can be associated in the processing phase.
-	statsCtx     context.Context
 	statsHandler stats.Handler
+	beginTime    time.Time
 }
 
 func (cs *clientStream) Context() context.Context {
-	return cs.s.Context()
+	// TODO(retry): commit the current attempt (the context has peer-aware data).
+	return cs.attempt.context()
 }
 
 func (cs *clientStream) Header() (metadata.MD, error) {
-	m, err := cs.s.Header()
+	m, err := cs.attempt.header()
 	if err != nil {
-		if _, ok := err.(transport.ConnectionError); !ok {
-			cs.closeTransportStream(err)
-		}
+		// TODO(retry): maybe retry on error or commit attempt on success.
+		err = toRPCErr(err)
+		cs.finish(err)
 	}
 	return m, err
 }
 
 func (cs *clientStream) Trailer() metadata.MD {
-	return cs.s.Trailer()
+	// TODO(retry): on error, maybe retry (trailers-only).
+	return cs.attempt.trailer()
 }
 
 func (cs *clientStream) SendMsg(m interface{}) (err error) {
-	if cs.tracing {
-		cs.mu.Lock()
-		if cs.trInfo.tr != nil {
-			cs.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
-		}
+	// TODO(retry): buffer message for replaying if not committed.
+	return cs.attempt.sendMsg(m)
+}
+
+func (cs *clientStream) RecvMsg(m interface{}) (err error) {
+	// TODO(retry): maybe retry on error or commit attempt on success.
+	return cs.attempt.recvMsg(m)
+}
+
+func (cs *clientStream) CloseSend() error {
+	cs.attempt.closeSend()
+	return nil
+}
+
+func (cs *clientStream) finish(err error) {
+	if err == io.EOF {
+		// Ending a stream with EOF indicates a success.
+		err = nil
+	}
+	cs.mu.Lock()
+	if cs.finished {
 		cs.mu.Unlock()
+		return
+	}
+	cs.finished = true
+	cs.mu.Unlock()
+	if channelz.IsOn() {
+		if err != nil {
+			cs.cc.incrCallsFailed()
+		} else {
+			cs.cc.incrCallsSucceeded()
+		}
+	}
+	// TODO(retry): commit current attempt if necessary.
+	cs.attempt.finish(err)
+	for _, o := range cs.opts {
+		o.after(cs.c)
 	}
+	cs.cancel()
+}
+
+func (a *csAttempt) context() context.Context {
+	return a.s.Context()
+}
+
+func (a *csAttempt) header() (metadata.MD, error) {
+	return a.s.Header()
+}
+
+func (a *csAttempt) trailer() metadata.MD {
+	return a.s.Trailer()
+}
+
+func (a *csAttempt) sendMsg(m interface{}) (err error) {
 	// TODO Investigate how to signal the stats handling party.
 	// generate error stats if err != nil && err != io.EOF?
+	cs := a.cs
 	defer func() {
-		if err != nil {
-			cs.finish(err)
-		}
-		if err == nil {
-			return
-		}
-		if err == io.EOF {
-			// Specialize the process for server streaming. SendMsg is only called
-			// once when creating the stream object. io.EOF needs to be skipped when
-			// the rpc is early finished (before the stream object is created.).
-			// TODO: It is probably better to move this into the generated code.
-			if !cs.desc.ClientStreams && cs.desc.ServerStreams {
-				err = nil
-			}
-			return
+		// For non-client-streaming RPCs, we return nil instead of EOF on success
+		// because the generated code requires it.  finish is not called; RecvMsg()
+		// will call it with the stream's status independently.
+		if err == io.EOF && !cs.desc.ClientStreams {
+			err = nil
 		}
-		if _, ok := err.(transport.ConnectionError); !ok {
-			cs.closeTransportStream(err)
+		if err != nil && err != io.EOF {
+			// Call finish on the client stream for errors generated by this SendMsg
+			// call, as these indicate problems created by this client.  (Transport
+			// errors are converted to an io.EOF error below; the real error will be
+			// returned from RecvMsg eventually in that case, or be retried.)
+			cs.finish(err)
 		}
-		err = toRPCErr(err)
 	}()
-	var outPayload *stats.OutPayload
-	if cs.statsHandler != nil {
-		outPayload = &stats.OutPayload{
-			Client: true,
+	// TODO: Check cs.sentLast and error if we already ended the stream.
+	if EnableTracing {
+		a.mu.Lock()
+		if a.trInfo.tr != nil {
+			a.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
 		}
+		a.mu.Unlock()
 	}
-	hdr, data, err := encode(cs.codec, m, cs.cp, bytes.NewBuffer([]byte{}), outPayload)
+	data, err := encode(cs.codec, m)
 	if err != nil {
 		return err
 	}
-	if cs.c.maxSendMessageSize == nil {
-		return Errorf(codes.Internal, "callInfo maxSendMessageSize field uninitialized(nil)")
+	compData, err := compress(data, cs.cp, cs.comp)
+	if err != nil {
+		return err
 	}
-	if len(data) > *cs.c.maxSendMessageSize {
-		return Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(data), *cs.c.maxSendMessageSize)
+	hdr, payload := msgHeader(data, compData)
+	// TODO(dfawley): should we be checking len(data) instead?
+	if len(payload) > *cs.c.maxSendMessageSize {
+		return status.Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(payload), *cs.c.maxSendMessageSize)
 	}
-	err = cs.t.Write(cs.s, hdr, data, &transport.Options{Last: false})
-	if err == nil && outPayload != nil {
-		outPayload.SentTime = time.Now()
-		cs.statsHandler.HandleRPC(cs.statsCtx, outPayload)
+
+	if !cs.desc.ClientStreams {
+		cs.sentLast = true
 	}
-	return err
+	err = a.t.Write(a.s, hdr, payload, &transport.Options{Last: !cs.desc.ClientStreams})
+	if err == nil {
+		if a.statsHandler != nil {
+			a.statsHandler.HandleRPC(a.ctx, outPayload(true, m, data, payload, time.Now()))
+		}
+		if channelz.IsOn() {
+			a.t.IncrMsgSent()
+		}
+		return nil
+	}
+	return io.EOF
 }
 
-func (cs *clientStream) RecvMsg(m interface{}) (err error) {
+func (a *csAttempt) recvMsg(m interface{}) (err error) {
+	cs := a.cs
+	defer func() {
+		if err != nil || !cs.desc.ServerStreams {
+			// err != nil or non-server-streaming indicates end of stream.
+			cs.finish(err)
+		}
+	}()
 	var inPayload *stats.InPayload
-	if cs.statsHandler != nil {
+	if a.statsHandler != nil {
 		inPayload = &stats.InPayload{
 			Client: true,
 		}
 	}
-	if cs.c.maxReceiveMessageSize == nil {
-		return Errorf(codes.Internal, "callInfo maxReceiveMessageSize field uninitialized(nil)")
-	}
-	err = recv(cs.p, cs.codec, cs.s, cs.dc, m, *cs.c.maxReceiveMessageSize, inPayload)
-	defer func() {
-		// err != nil indicates the termination of the stream.
-		if err != nil {
-			cs.finish(err)
-		}
-	}()
-	if err == nil {
-		if cs.tracing {
-			cs.mu.Lock()
-			if cs.trInfo.tr != nil {
-				cs.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
+	if !a.decompSet {
+		// Block until we receive headers containing received message encoding.
+		if ct := a.s.RecvCompress(); ct != "" && ct != encoding.Identity {
+			if a.dc == nil || a.dc.Type() != ct {
+				// No configured decompressor, or it does not match the incoming
+				// message encoding; attempt to find a registered compressor that does.
+				a.dc = nil
+				a.decomp = encoding.GetCompressor(ct)
 			}
-			cs.mu.Unlock()
-		}
-		if inPayload != nil {
-			cs.statsHandler.HandleRPC(cs.statsCtx, inPayload)
-		}
-		if !cs.desc.ClientStreams || cs.desc.ServerStreams {
-			return
-		}
-		// Special handling for client streaming rpc.
-		// This recv expects EOF or errors, so we don't collect inPayload.
-		if cs.c.maxReceiveMessageSize == nil {
-			return Errorf(codes.Internal, "callInfo maxReceiveMessageSize field uninitialized(nil)")
-		}
-		err = recv(cs.p, cs.codec, cs.s, cs.dc, m, *cs.c.maxReceiveMessageSize, nil)
-		cs.closeTransportStream(err)
-		if err == nil {
-			return toRPCErr(errors.New("grpc: client streaming protocol violation: get <nil>, want <EOF>"))
+		} else {
+			// No compression is used; disable our decompressor.
+			a.dc = nil
 		}
+		// Only initialize this state once per stream.
+		a.decompSet = true
+	}
+	err = recv(a.p, cs.codec, a.s, a.dc, m, *cs.c.maxReceiveMessageSize, inPayload, a.decomp)
+	if err != nil {
 		if err == io.EOF {
-			if se := cs.s.Status().Err(); se != nil {
-				return se
+			if statusErr := a.s.Status().Err(); statusErr != nil {
+				return statusErr
 			}
-			cs.finish(err)
-			return nil
+			return io.EOF // indicates successful end of stream.
 		}
 		return toRPCErr(err)
 	}
-	if _, ok := err.(transport.ConnectionError); !ok {
-		cs.closeTransportStream(err)
-	}
-	if err == io.EOF {
-		if statusErr := cs.s.Status().Err(); statusErr != nil {
-			return statusErr
+	if EnableTracing {
+		a.mu.Lock()
+		if a.trInfo.tr != nil {
+			a.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
 		}
-		// Returns io.EOF to indicate the end of the stream.
-		return
+		a.mu.Unlock()
 	}
-	return toRPCErr(err)
-}
-
-func (cs *clientStream) CloseSend() (err error) {
-	err = cs.t.Write(cs.s, nil, nil, &transport.Options{Last: true})
-	defer func() {
-		if err != nil {
-			cs.finish(err)
-		}
-	}()
-	if err == nil || err == io.EOF {
+	if inPayload != nil {
+		a.statsHandler.HandleRPC(a.ctx, inPayload)
+	}
+	if channelz.IsOn() {
+		a.t.IncrMsgRecv()
+	}
+	if cs.desc.ServerStreams {
+		// Subsequent messages should be received by subsequent RecvMsg calls.
 		return nil
 	}
-	if _, ok := err.(transport.ConnectionError); !ok {
-		cs.closeTransportStream(err)
+
+	// Special handling for non-server-stream rpcs.
+	// This recv expects EOF or errors, so we don't collect inPayload.
+	err = recv(a.p, cs.codec, a.s, a.dc, m, *cs.c.maxReceiveMessageSize, nil, a.decomp)
+	if err == nil {
+		return toRPCErr(errors.New("grpc: client streaming protocol violation: get <nil>, want <EOF>"))
+	}
+	if err == io.EOF {
+		return a.s.Status().Err() // non-server streaming Recv returns nil on success
 	}
-	err = toRPCErr(err)
-	return
+	return toRPCErr(err)
 }
 
-func (cs *clientStream) closeTransportStream(err error) {
-	cs.mu.Lock()
-	if cs.closed {
-		cs.mu.Unlock()
+func (a *csAttempt) closeSend() {
+	cs := a.cs
+	if cs.sentLast {
 		return
 	}
-	cs.closed = true
-	cs.mu.Unlock()
-	cs.t.CloseStream(cs.s, err)
+	cs.sentLast = true
+	cs.attempt.t.Write(cs.attempt.s, nil, nil, &transport.Options{Last: true})
+	// We ignore errors from Write.  Any error it would return would also be
+	// returned by a subsequent RecvMsg call, and the user is supposed to always
+	// finish the stream by calling RecvMsg until it returns err != nil.
 }
 
-func (cs *clientStream) finish(err error) {
-	cs.mu.Lock()
-	defer cs.mu.Unlock()
-	if cs.finished {
-		return
-	}
-	cs.finished = true
-	defer func() {
-		if cs.cancel != nil {
-			cs.cancel()
-		}
-	}()
-	for _, o := range cs.opts {
-		o.after(cs.c)
-	}
-	if cs.done != nil {
-		updateRPCInfoInContext(cs.s.Context(), rpcInfo{
-			bytesSent:     cs.s.BytesSent(),
-			bytesReceived: cs.s.BytesReceived(),
+func (a *csAttempt) finish(err error) {
+	a.mu.Lock()
+	a.t.CloseStream(a.s, err)
+
+	if a.done != nil {
+		a.done(balancer.DoneInfo{
+			Err:           err,
+			BytesSent:     true,
+			BytesReceived: a.s.BytesReceived(),
 		})
-		cs.done(balancer.DoneInfo{Err: err})
-		cs.done = nil
 	}
-	if cs.statsHandler != nil {
+	if a.statsHandler != nil {
 		end := &stats.End{
-			Client:  true,
-			EndTime: time.Now(),
-		}
-		if err != io.EOF {
-			// end.Error is nil if the RPC finished successfully.
-			end.Error = toRPCErr(err)
+			Client:    true,
+			BeginTime: a.beginTime,
+			EndTime:   time.Now(),
+			Error:     err,
 		}
-		cs.statsHandler.HandleRPC(cs.statsCtx, end)
-	}
-	if !cs.tracing {
-		return
+		a.statsHandler.HandleRPC(a.ctx, end)
 	}
-	if cs.trInfo.tr != nil {
-		if err == nil || err == io.EOF {
-			cs.trInfo.tr.LazyPrintf("RPC: [OK]")
+	if a.trInfo.tr != nil {
+		if err == nil {
+			a.trInfo.tr.LazyPrintf("RPC: [OK]")
 		} else {
-			cs.trInfo.tr.LazyPrintf("RPC: [%v]", err)
-			cs.trInfo.tr.SetError()
+			a.trInfo.tr.LazyPrintf("RPC: [%v]", err)
+			a.trInfo.tr.SetError()
 		}
-		cs.trInfo.tr.Finish()
-		cs.trInfo.tr = nil
+		a.trInfo.tr.Finish()
+		a.trInfo.tr = nil
 	}
+	a.mu.Unlock()
 }
 
 // ServerStream defines the interface a server stream has to satisfy.
@@ -540,12 +645,17 @@ type ServerStream interface {
 
 // serverStream implements a server side Stream.
 type serverStream struct {
-	t                     transport.ServerTransport
-	s                     *transport.Stream
-	p                     *parser
-	codec                 Codec
-	cp                    Compressor
-	dc                    Decompressor
+	ctx   context.Context
+	t     transport.ServerTransport
+	s     *transport.Stream
+	p     *parser
+	codec baseCodec
+
+	cp     Compressor
+	dc     Decompressor
+	comp   encoding.Compressor
+	decomp encoding.Compressor
+
 	maxReceiveMessageSize int
 	maxSendMessageSize    int
 	trInfo                *traceInfo
@@ -556,7 +666,7 @@ type serverStream struct {
 }
 
 func (ss *serverStream) Context() context.Context {
-	return ss.s.Context()
+	return ss.ctx
 }
 
 func (ss *serverStream) SetHeader(md metadata.MD) error {
@@ -575,7 +685,6 @@ func (ss *serverStream) SetTrailer(md metadata.MD) {
 		return
 	}
 	ss.s.SetTrailer(md)
-	return
 }
 
 func (ss *serverStream) SendMsg(m interface{}) (err error) {
@@ -596,24 +705,28 @@ func (ss *serverStream) SendMsg(m interface{}) (err error) {
 			st, _ := status.FromError(toRPCErr(err))
 			ss.t.WriteStatus(ss.s, st)
 		}
+		if channelz.IsOn() && err == nil {
+			ss.t.IncrMsgSent()
+		}
 	}()
-	var outPayload *stats.OutPayload
-	if ss.statsHandler != nil {
-		outPayload = &stats.OutPayload{}
+	data, err := encode(ss.codec, m)
+	if err != nil {
+		return err
 	}
-	hdr, data, err := encode(ss.codec, m, ss.cp, bytes.NewBuffer([]byte{}), outPayload)
+	compData, err := compress(data, ss.cp, ss.comp)
 	if err != nil {
 		return err
 	}
-	if len(data) > ss.maxSendMessageSize {
-		return Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(data), ss.maxSendMessageSize)
+	hdr, payload := msgHeader(data, compData)
+	// TODO(dfawley): should we be checking len(data) instead?
+	if len(payload) > ss.maxSendMessageSize {
+		return status.Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(payload), ss.maxSendMessageSize)
 	}
-	if err := ss.t.Write(ss.s, hdr, data, &transport.Options{Last: false}); err != nil {
+	if err := ss.t.Write(ss.s, hdr, payload, &transport.Options{Last: false}); err != nil {
 		return toRPCErr(err)
 	}
-	if outPayload != nil {
-		outPayload.SentTime = time.Now()
-		ss.statsHandler.HandleRPC(ss.s.Context(), outPayload)
+	if ss.statsHandler != nil {
+		ss.statsHandler.HandleRPC(ss.s.Context(), outPayload(false, m, data, payload, time.Now()))
 	}
 	return nil
 }
@@ -636,17 +749,20 @@ func (ss *serverStream) RecvMsg(m interface{}) (err error) {
 			st, _ := status.FromError(toRPCErr(err))
 			ss.t.WriteStatus(ss.s, st)
 		}
+		if channelz.IsOn() && err == nil {
+			ss.t.IncrMsgRecv()
+		}
 	}()
 	var inPayload *stats.InPayload
 	if ss.statsHandler != nil {
 		inPayload = &stats.InPayload{}
 	}
-	if err := recv(ss.p, ss.codec, ss.s, ss.dc, m, ss.maxReceiveMessageSize, inPayload); err != nil {
+	if err := recv(ss.p, ss.codec, ss.s, ss.dc, m, ss.maxReceiveMessageSize, inPayload, ss.decomp); err != nil {
 		if err == io.EOF {
 			return err
 		}
 		if err == io.ErrUnexpectedEOF {
-			err = Errorf(codes.Internal, io.ErrUnexpectedEOF.Error())
+			err = status.Errorf(codes.Internal, io.ErrUnexpectedEOF.Error())
 		}
 		return toRPCErr(err)
 	}
@@ -655,3 +771,9 @@ func (ss *serverStream) RecvMsg(m interface{}) (err error) {
 	}
 	return nil
 }
+
+// MethodFromServerStream returns the method string for the input stream.
+// The returned string is in the format of "/service/method".
+func MethodFromServerStream(stream ServerStream) (string, bool) {
+	return Method(stream.Context())
+}
diff --git a/vendor/google.golang.org/grpc/transport/bdp_estimator.go b/vendor/google.golang.org/grpc/transport/bdp_estimator.go
index 8dd2ed4..63cd262 100644
--- a/vendor/google.golang.org/grpc/transport/bdp_estimator.go
+++ b/vendor/google.golang.org/grpc/transport/bdp_estimator.go
@@ -41,12 +41,9 @@ const (
 	gamma = 2
 )
 
-var (
-	// Adding arbitrary data to ping so that its ack can be
-	// identified.
-	// Easter-egg: what does the ping message say?
-	bdpPing = &ping{data: [8]byte{2, 4, 16, 16, 9, 14, 7, 7}}
-)
+// Adding arbitrary data to ping so that its ack can be identified.
+// Easter-egg: what does the ping message say?
+var bdpPing = &ping{data: [8]byte{2, 4, 16, 16, 9, 14, 7, 7}}
 
 type bdpEstimator struct {
 	// sentAt is the time when the ping was sent.
diff --git a/vendor/google.golang.org/grpc/transport/controlbuf.go b/vendor/google.golang.org/grpc/transport/controlbuf.go
new file mode 100644
index 0000000..5c5891a
--- /dev/null
+++ b/vendor/google.golang.org/grpc/transport/controlbuf.go
@@ -0,0 +1,796 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package transport
+
+import (
+	"bytes"
+	"fmt"
+	"runtime"
+	"sync"
+
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/hpack"
+)
+
+var updateHeaderTblSize = func(e *hpack.Encoder, v uint32) {
+	e.SetMaxDynamicTableSizeLimit(v)
+}
+
+type itemNode struct {
+	it   interface{}
+	next *itemNode
+}
+
+type itemList struct {
+	head *itemNode
+	tail *itemNode
+}
+
+func (il *itemList) enqueue(i interface{}) {
+	n := &itemNode{it: i}
+	if il.tail == nil {
+		il.head, il.tail = n, n
+		return
+	}
+	il.tail.next = n
+	il.tail = n
+}
+
+// peek returns the first item in the list without removing it from the
+// list.
+func (il *itemList) peek() interface{} {
+	return il.head.it
+}
+
+func (il *itemList) dequeue() interface{} {
+	if il.head == nil {
+		return nil
+	}
+	i := il.head.it
+	il.head = il.head.next
+	if il.head == nil {
+		il.tail = nil
+	}
+	return i
+}
+
+func (il *itemList) dequeueAll() *itemNode {
+	h := il.head
+	il.head, il.tail = nil, nil
+	return h
+}
+
+func (il *itemList) isEmpty() bool {
+	return il.head == nil
+}
+
+// The following defines various control items which could flow through
+// the control buffer of transport. They represent different aspects of
+// control tasks, e.g., flow control, settings, streaming resetting, etc.
+
+// registerStream is used to register an incoming stream with loopy writer.
+type registerStream struct {
+	streamID uint32
+	wq       *writeQuota
+}
+
+// headerFrame is also used to register stream on the client-side.
+type headerFrame struct {
+	streamID   uint32
+	hf         []hpack.HeaderField
+	endStream  bool                       // Valid on server side.
+	initStream func(uint32) (bool, error) // Used only on the client side.
+	onWrite    func()
+	wq         *writeQuota    // write quota for the stream created.
+	cleanup    *cleanupStream // Valid on the server side.
+	onOrphaned func(error)    // Valid on client-side
+}
+
+type cleanupStream struct {
+	streamID uint32
+	idPtr    *uint32
+	rst      bool
+	rstCode  http2.ErrCode
+	onWrite  func()
+}
+
+type dataFrame struct {
+	streamID  uint32
+	endStream bool
+	h         []byte
+	d         []byte
+	// onEachWrite is called every time
+	// a part of d is written out.
+	onEachWrite func()
+}
+
+type incomingWindowUpdate struct {
+	streamID  uint32
+	increment uint32
+}
+
+type outgoingWindowUpdate struct {
+	streamID  uint32
+	increment uint32
+}
+
+type incomingSettings struct {
+	ss []http2.Setting
+}
+
+type outgoingSettings struct {
+	ss []http2.Setting
+}
+
+type settingsAck struct {
+}
+
+type incomingGoAway struct {
+}
+
+type goAway struct {
+	code      http2.ErrCode
+	debugData []byte
+	headsUp   bool
+	closeConn bool
+}
+
+type ping struct {
+	ack  bool
+	data [8]byte
+}
+
+type outFlowControlSizeRequest struct {
+	resp chan uint32
+}
+
+type outStreamState int
+
+const (
+	active outStreamState = iota
+	empty
+	waitingOnStreamQuota
+)
+
+type outStream struct {
+	id               uint32
+	state            outStreamState
+	itl              *itemList
+	bytesOutStanding int
+	wq               *writeQuota
+
+	next *outStream
+	prev *outStream
+}
+
+func (s *outStream) deleteSelf() {
+	if s.prev != nil {
+		s.prev.next = s.next
+	}
+	if s.next != nil {
+		s.next.prev = s.prev
+	}
+	s.next, s.prev = nil, nil
+}
+
+type outStreamList struct {
+	// Following are sentinel objects that mark the
+	// beginning and end of the list. They do not
+	// contain any item lists. All valid objects are
+	// inserted in between them.
+	// This is needed so that an outStream object can
+	// deleteSelf() in O(1) time without knowing which
+	// list it belongs to.
+	head *outStream
+	tail *outStream
+}
+
+func newOutStreamList() *outStreamList {
+	head, tail := new(outStream), new(outStream)
+	head.next = tail
+	tail.prev = head
+	return &outStreamList{
+		head: head,
+		tail: tail,
+	}
+}
+
+func (l *outStreamList) enqueue(s *outStream) {
+	e := l.tail.prev
+	e.next = s
+	s.prev = e
+	s.next = l.tail
+	l.tail.prev = s
+}
+
+// remove from the beginning of the list.
+func (l *outStreamList) dequeue() *outStream {
+	b := l.head.next
+	if b == l.tail {
+		return nil
+	}
+	b.deleteSelf()
+	return b
+}
+
+type controlBuffer struct {
+	ch              chan struct{}
+	done            <-chan struct{}
+	mu              sync.Mutex
+	consumerWaiting bool
+	list            *itemList
+	err             error
+}
+
+func newControlBuffer(done <-chan struct{}) *controlBuffer {
+	return &controlBuffer{
+		ch:   make(chan struct{}, 1),
+		list: &itemList{},
+		done: done,
+	}
+}
+
+func (c *controlBuffer) put(it interface{}) error {
+	_, err := c.executeAndPut(nil, it)
+	return err
+}
+
+func (c *controlBuffer) executeAndPut(f func(it interface{}) bool, it interface{}) (bool, error) {
+	var wakeUp bool
+	c.mu.Lock()
+	if c.err != nil {
+		c.mu.Unlock()
+		return false, c.err
+	}
+	if f != nil {
+		if !f(it) { // f wasn't successful
+			c.mu.Unlock()
+			return false, nil
+		}
+	}
+	if c.consumerWaiting {
+		wakeUp = true
+		c.consumerWaiting = false
+	}
+	c.list.enqueue(it)
+	c.mu.Unlock()
+	if wakeUp {
+		select {
+		case c.ch <- struct{}{}:
+		default:
+		}
+	}
+	return true, nil
+}
+
+func (c *controlBuffer) get(block bool) (interface{}, error) {
+	for {
+		c.mu.Lock()
+		if c.err != nil {
+			c.mu.Unlock()
+			return nil, c.err
+		}
+		if !c.list.isEmpty() {
+			h := c.list.dequeue()
+			c.mu.Unlock()
+			return h, nil
+		}
+		if !block {
+			c.mu.Unlock()
+			return nil, nil
+		}
+		c.consumerWaiting = true
+		c.mu.Unlock()
+		select {
+		case <-c.ch:
+		case <-c.done:
+			c.finish()
+			return nil, ErrConnClosing
+		}
+	}
+}
+
+func (c *controlBuffer) finish() {
+	c.mu.Lock()
+	if c.err != nil {
+		c.mu.Unlock()
+		return
+	}
+	c.err = ErrConnClosing
+	// There may be headers for streams in the control buffer.
+	// These streams need to be cleaned out since the transport
+	// is still not aware of these yet.
+	for head := c.list.dequeueAll(); head != nil; head = head.next {
+		hdr, ok := head.it.(*headerFrame)
+		if !ok {
+			continue
+		}
+		if hdr.onOrphaned != nil { // It will be nil on the server-side.
+			hdr.onOrphaned(ErrConnClosing)
+		}
+	}
+	c.mu.Unlock()
+}
+
+type side int
+
+const (
+	clientSide side = iota
+	serverSide
+)
+
+type loopyWriter struct {
+	side          side
+	cbuf          *controlBuffer
+	sendQuota     uint32
+	oiws          uint32                // outbound initial window size.
+	estdStreams   map[uint32]*outStream // Established streams.
+	activeStreams *outStreamList        // Streams that are sending data.
+	framer        *framer
+	hBuf          *bytes.Buffer  // The buffer for HPACK encoding.
+	hEnc          *hpack.Encoder // HPACK encoder.
+	bdpEst        *bdpEstimator
+	draining      bool
+
+	// Side-specific handlers
+	ssGoAwayHandler func(*goAway) (bool, error)
+}
+
+func newLoopyWriter(s side, fr *framer, cbuf *controlBuffer, bdpEst *bdpEstimator) *loopyWriter {
+	var buf bytes.Buffer
+	l := &loopyWriter{
+		side:          s,
+		cbuf:          cbuf,
+		sendQuota:     defaultWindowSize,
+		oiws:          defaultWindowSize,
+		estdStreams:   make(map[uint32]*outStream),
+		activeStreams: newOutStreamList(),
+		framer:        fr,
+		hBuf:          &buf,
+		hEnc:          hpack.NewEncoder(&buf),
+		bdpEst:        bdpEst,
+	}
+	return l
+}
+
+const minBatchSize = 1000
+
+// run should be run in a separate goroutine.
+func (l *loopyWriter) run() (err error) {
+	defer func() {
+		if err == ErrConnClosing {
+			// Don't log ErrConnClosing as error since it happens
+			// 1. When the connection is closed by some other known issue.
+			// 2. User closed the connection.
+			// 3. A graceful close of connection.
+			infof("transport: loopyWriter.run returning. %v", err)
+			err = nil
+		}
+	}()
+	for {
+		it, err := l.cbuf.get(true)
+		if err != nil {
+			return err
+		}
+		if err = l.handle(it); err != nil {
+			return err
+		}
+		if _, err = l.processData(); err != nil {
+			return err
+		}
+		gosched := true
+	hasdata:
+		for {
+			it, err := l.cbuf.get(false)
+			if err != nil {
+				return err
+			}
+			if it != nil {
+				if err = l.handle(it); err != nil {
+					return err
+				}
+				if _, err = l.processData(); err != nil {
+					return err
+				}
+				continue hasdata
+			}
+			isEmpty, err := l.processData()
+			if err != nil {
+				return err
+			}
+			if !isEmpty {
+				continue hasdata
+			}
+			if gosched {
+				gosched = false
+				if l.framer.writer.offset < minBatchSize {
+					runtime.Gosched()
+					continue hasdata
+				}
+			}
+			l.framer.writer.Flush()
+			break hasdata
+
+		}
+	}
+}
+
+func (l *loopyWriter) outgoingWindowUpdateHandler(w *outgoingWindowUpdate) error {
+	return l.framer.fr.WriteWindowUpdate(w.streamID, w.increment)
+}
+
+func (l *loopyWriter) incomingWindowUpdateHandler(w *incomingWindowUpdate) error {
+	// Otherwise update the quota.
+	if w.streamID == 0 {
+		l.sendQuota += w.increment
+		return nil
+	}
+	// Find the stream and update it.
+	if str, ok := l.estdStreams[w.streamID]; ok {
+		str.bytesOutStanding -= int(w.increment)
+		if strQuota := int(l.oiws) - str.bytesOutStanding; strQuota > 0 && str.state == waitingOnStreamQuota {
+			str.state = active
+			l.activeStreams.enqueue(str)
+			return nil
+		}
+	}
+	return nil
+}
+
+func (l *loopyWriter) outgoingSettingsHandler(s *outgoingSettings) error {
+	return l.framer.fr.WriteSettings(s.ss...)
+}
+
+func (l *loopyWriter) incomingSettingsHandler(s *incomingSettings) error {
+	if err := l.applySettings(s.ss); err != nil {
+		return err
+	}
+	return l.framer.fr.WriteSettingsAck()
+}
+
+func (l *loopyWriter) registerStreamHandler(h *registerStream) error {
+	str := &outStream{
+		id:    h.streamID,
+		state: empty,
+		itl:   &itemList{},
+		wq:    h.wq,
+	}
+	l.estdStreams[h.streamID] = str
+	return nil
+}
+
+func (l *loopyWriter) headerHandler(h *headerFrame) error {
+	if l.side == serverSide {
+		str, ok := l.estdStreams[h.streamID]
+		if !ok {
+			warningf("transport: loopy doesn't recognize the stream: %d", h.streamID)
+			return nil
+		}
+		// Case 1.A: Server is responding back with headers.
+		if !h.endStream {
+			return l.writeHeader(h.streamID, h.endStream, h.hf, h.onWrite)
+		}
+		// else:  Case 1.B: Server wants to close stream.
+
+		if str.state != empty { // either active or waiting on stream quota.
+			// add it str's list of items.
+			str.itl.enqueue(h)
+			return nil
+		}
+		if err := l.writeHeader(h.streamID, h.endStream, h.hf, h.onWrite); err != nil {
+			return err
+		}
+		return l.cleanupStreamHandler(h.cleanup)
+	}
+	// Case 2: Client wants to originate stream.
+	str := &outStream{
+		id:    h.streamID,
+		state: empty,
+		itl:   &itemList{},
+		wq:    h.wq,
+	}
+	str.itl.enqueue(h)
+	return l.originateStream(str)
+}
+
+func (l *loopyWriter) originateStream(str *outStream) error {
+	hdr := str.itl.dequeue().(*headerFrame)
+	sendPing, err := hdr.initStream(str.id)
+	if err != nil {
+		if err == ErrConnClosing {
+			return err
+		}
+		// Other errors(errStreamDrain) need not close transport.
+		return nil
+	}
+	if err = l.writeHeader(str.id, hdr.endStream, hdr.hf, hdr.onWrite); err != nil {
+		return err
+	}
+	l.estdStreams[str.id] = str
+	if sendPing {
+		return l.pingHandler(&ping{data: [8]byte{}})
+	}
+	return nil
+}
+
+func (l *loopyWriter) writeHeader(streamID uint32, endStream bool, hf []hpack.HeaderField, onWrite func()) error {
+	if onWrite != nil {
+		onWrite()
+	}
+	l.hBuf.Reset()
+	for _, f := range hf {
+		if err := l.hEnc.WriteField(f); err != nil {
+			warningf("transport: loopyWriter.writeHeader encountered error while encoding headers:", err)
+		}
+	}
+	var (
+		err               error
+		endHeaders, first bool
+	)
+	first = true
+	for !endHeaders {
+		size := l.hBuf.Len()
+		if size > http2MaxFrameLen {
+			size = http2MaxFrameLen
+		} else {
+			endHeaders = true
+		}
+		if first {
+			first = false
+			err = l.framer.fr.WriteHeaders(http2.HeadersFrameParam{
+				StreamID:      streamID,
+				BlockFragment: l.hBuf.Next(size),
+				EndStream:     endStream,
+				EndHeaders:    endHeaders,
+			})
+		} else {
+			err = l.framer.fr.WriteContinuation(
+				streamID,
+				endHeaders,
+				l.hBuf.Next(size),
+			)
+		}
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (l *loopyWriter) preprocessData(df *dataFrame) error {
+	str, ok := l.estdStreams[df.streamID]
+	if !ok {
+		return nil
+	}
+	// If we got data for a stream it means that
+	// stream was originated and the headers were sent out.
+	str.itl.enqueue(df)
+	if str.state == empty {
+		str.state = active
+		l.activeStreams.enqueue(str)
+	}
+	return nil
+}
+
+func (l *loopyWriter) pingHandler(p *ping) error {
+	if !p.ack {
+		l.bdpEst.timesnap(p.data)
+	}
+	return l.framer.fr.WritePing(p.ack, p.data)
+
+}
+
+func (l *loopyWriter) outFlowControlSizeRequestHandler(o *outFlowControlSizeRequest) error {
+	o.resp <- l.sendQuota
+	return nil
+}
+
+func (l *loopyWriter) cleanupStreamHandler(c *cleanupStream) error {
+	c.onWrite()
+	if str, ok := l.estdStreams[c.streamID]; ok {
+		// On the server side it could be a trailers-only response or
+		// a RST_STREAM before stream initialization thus the stream might
+		// not be established yet.
+		delete(l.estdStreams, c.streamID)
+		str.deleteSelf()
+	}
+	if c.rst { // If RST_STREAM needs to be sent.
+		if err := l.framer.fr.WriteRSTStream(c.streamID, c.rstCode); err != nil {
+			return err
+		}
+	}
+	if l.side == clientSide && l.draining && len(l.estdStreams) == 0 {
+		return ErrConnClosing
+	}
+	return nil
+}
+
+func (l *loopyWriter) incomingGoAwayHandler(*incomingGoAway) error {
+	if l.side == clientSide {
+		l.draining = true
+		if len(l.estdStreams) == 0 {
+			return ErrConnClosing
+		}
+	}
+	return nil
+}
+
+func (l *loopyWriter) goAwayHandler(g *goAway) error {
+	// Handling of outgoing GoAway is very specific to side.
+	if l.ssGoAwayHandler != nil {
+		draining, err := l.ssGoAwayHandler(g)
+		if err != nil {
+			return err
+		}
+		l.draining = draining
+	}
+	return nil
+}
+
+func (l *loopyWriter) handle(i interface{}) error {
+	switch i := i.(type) {
+	case *incomingWindowUpdate:
+		return l.incomingWindowUpdateHandler(i)
+	case *outgoingWindowUpdate:
+		return l.outgoingWindowUpdateHandler(i)
+	case *incomingSettings:
+		return l.incomingSettingsHandler(i)
+	case *outgoingSettings:
+		return l.outgoingSettingsHandler(i)
+	case *headerFrame:
+		return l.headerHandler(i)
+	case *registerStream:
+		return l.registerStreamHandler(i)
+	case *cleanupStream:
+		return l.cleanupStreamHandler(i)
+	case *incomingGoAway:
+		return l.incomingGoAwayHandler(i)
+	case *dataFrame:
+		return l.preprocessData(i)
+	case *ping:
+		return l.pingHandler(i)
+	case *goAway:
+		return l.goAwayHandler(i)
+	case *outFlowControlSizeRequest:
+		return l.outFlowControlSizeRequestHandler(i)
+	default:
+		return fmt.Errorf("transport: unknown control message type %T", i)
+	}
+}
+
+func (l *loopyWriter) applySettings(ss []http2.Setting) error {
+	for _, s := range ss {
+		switch s.ID {
+		case http2.SettingInitialWindowSize:
+			o := l.oiws
+			l.oiws = s.Val
+			if o < l.oiws {
+				// If the new limit is greater make all depleted streams active.
+				for _, stream := range l.estdStreams {
+					if stream.state == waitingOnStreamQuota {
+						stream.state = active
+						l.activeStreams.enqueue(stream)
+					}
+				}
+			}
+		case http2.SettingHeaderTableSize:
+			updateHeaderTblSize(l.hEnc, s.Val)
+		}
+	}
+	return nil
+}
+
+func (l *loopyWriter) processData() (bool, error) {
+	if l.sendQuota == 0 {
+		return true, nil
+	}
+	str := l.activeStreams.dequeue()
+	if str == nil {
+		return true, nil
+	}
+	dataItem := str.itl.peek().(*dataFrame)
+	if len(dataItem.h) == 0 && len(dataItem.d) == 0 {
+		// Client sends out empty data frame with endStream = true
+		if err := l.framer.fr.WriteData(dataItem.streamID, dataItem.endStream, nil); err != nil {
+			return false, err
+		}
+		str.itl.dequeue()
+		if str.itl.isEmpty() {
+			str.state = empty
+		} else if trailer, ok := str.itl.peek().(*headerFrame); ok { // the next item is trailers.
+			if err := l.writeHeader(trailer.streamID, trailer.endStream, trailer.hf, trailer.onWrite); err != nil {
+				return false, err
+			}
+			if err := l.cleanupStreamHandler(trailer.cleanup); err != nil {
+				return false, nil
+			}
+		} else {
+			l.activeStreams.enqueue(str)
+		}
+		return false, nil
+	}
+	var (
+		idx int
+		buf []byte
+	)
+	if len(dataItem.h) != 0 { // data header has not been written out yet.
+		buf = dataItem.h
+	} else {
+		idx = 1
+		buf = dataItem.d
+	}
+	size := http2MaxFrameLen
+	if len(buf) < size {
+		size = len(buf)
+	}
+	if strQuota := int(l.oiws) - str.bytesOutStanding; strQuota <= 0 {
+		str.state = waitingOnStreamQuota
+		return false, nil
+	} else if strQuota < size {
+		size = strQuota
+	}
+
+	if l.sendQuota < uint32(size) {
+		size = int(l.sendQuota)
+	}
+	// Now that outgoing flow controls are checked we can replenish str's write quota
+	str.wq.replenish(size)
+	var endStream bool
+	// This last data message on this stream and all
+	// of it can be written in this go.
+	if dataItem.endStream && size == len(buf) {
+		// buf contains either data or it contains header but data is empty.
+		if idx == 1 || len(dataItem.d) == 0 {
+			endStream = true
+		}
+	}
+	if dataItem.onEachWrite != nil {
+		dataItem.onEachWrite()
+	}
+	if err := l.framer.fr.WriteData(dataItem.streamID, endStream, buf[:size]); err != nil {
+		return false, err
+	}
+	buf = buf[size:]
+	str.bytesOutStanding += size
+	l.sendQuota -= uint32(size)
+	if idx == 0 {
+		dataItem.h = buf
+	} else {
+		dataItem.d = buf
+	}
+
+	if len(dataItem.h) == 0 && len(dataItem.d) == 0 { // All the data from that message was written out.
+		str.itl.dequeue()
+	}
+	if str.itl.isEmpty() {
+		str.state = empty
+	} else if trailer, ok := str.itl.peek().(*headerFrame); ok { // The next item is trailers.
+		if err := l.writeHeader(trailer.streamID, trailer.endStream, trailer.hf, trailer.onWrite); err != nil {
+			return false, err
+		}
+		if err := l.cleanupStreamHandler(trailer.cleanup); err != nil {
+			return false, err
+		}
+	} else if int(l.oiws)-str.bytesOutStanding <= 0 { // Ran out of stream quota.
+		str.state = waitingOnStreamQuota
+	} else { // Otherwise add it back to the list of active streams.
+		l.activeStreams.enqueue(str)
+	}
+	return false, nil
+}
diff --git a/vendor/google.golang.org/grpc/transport/control.go b/vendor/google.golang.org/grpc/transport/flowcontrol.go
index dd1a8d4..bbf98b6 100644
--- a/vendor/google.golang.org/grpc/transport/control.go
+++ b/vendor/google.golang.org/grpc/transport/flowcontrol.go
@@ -24,9 +24,6 @@ import (
 	"sync"
 	"sync/atomic"
 	"time"
-
-	"golang.org/x/net/http2"
-	"golang.org/x/net/http2/hpack"
 )
 
 const (
@@ -36,179 +33,115 @@ const (
 	initialWindowSize             = defaultWindowSize // for an RPC
 	infinity                      = time.Duration(math.MaxInt64)
 	defaultClientKeepaliveTime    = infinity
-	defaultClientKeepaliveTimeout = time.Duration(20 * time.Second)
+	defaultClientKeepaliveTimeout = 20 * time.Second
 	defaultMaxStreamsClient       = 100
 	defaultMaxConnectionIdle      = infinity
 	defaultMaxConnectionAge       = infinity
 	defaultMaxConnectionAgeGrace  = infinity
-	defaultServerKeepaliveTime    = time.Duration(2 * time.Hour)
-	defaultServerKeepaliveTimeout = time.Duration(20 * time.Second)
-	defaultKeepalivePolicyMinTime = time.Duration(5 * time.Minute)
+	defaultServerKeepaliveTime    = 2 * time.Hour
+	defaultServerKeepaliveTimeout = 20 * time.Second
+	defaultKeepalivePolicyMinTime = 5 * time.Minute
 	// max window limit set by HTTP2 Specs.
 	maxWindowSize = math.MaxInt32
-	// defaultLocalSendQuota sets is default value for number of data
+	// defaultWriteQuota is the default value for number of data
 	// bytes that each stream can schedule before some of it being
 	// flushed out.
-	defaultLocalSendQuota = 64 * 1024
+	defaultWriteQuota = 64 * 1024
 )
 
-// The following defines various control items which could flow through
-// the control buffer of transport. They represent different aspects of
-// control tasks, e.g., flow control, settings, streaming resetting, etc.
-
-type headerFrame struct {
-	streamID  uint32
-	hf        []hpack.HeaderField
-	endStream bool
-}
-
-func (*headerFrame) item() {}
-
-type continuationFrame struct {
-	streamID            uint32
-	endHeaders          bool
-	headerBlockFragment []byte
-}
-
-type dataFrame struct {
-	streamID  uint32
-	endStream bool
-	d         []byte
-	f         func()
-}
-
-func (*dataFrame) item() {}
-
-func (*continuationFrame) item() {}
-
-type windowUpdate struct {
-	streamID  uint32
-	increment uint32
-}
-
-func (*windowUpdate) item() {}
-
-type settings struct {
-	ack bool
-	ss  []http2.Setting
-}
-
-func (*settings) item() {}
-
-type resetStream struct {
-	streamID uint32
-	code     http2.ErrCode
-}
-
-func (*resetStream) item() {}
-
-type goAway struct {
-	code      http2.ErrCode
-	debugData []byte
-	headsUp   bool
-	closeConn bool
-}
-
-func (*goAway) item() {}
-
-type flushIO struct {
-}
-
-func (*flushIO) item() {}
-
-type ping struct {
-	ack  bool
-	data [8]byte
+// writeQuota is a soft limit on the amount of data a stream can
+// schedule before some of it is written out.
+type writeQuota struct {
+	quota int32
+	// get waits on read from when quota goes less than or equal to zero.
+	// replenish writes on it when quota goes positive again.
+	ch chan struct{}
+	// done is triggered in error case.
+	done <-chan struct{}
+	// replenish is called by loopyWriter to give quota back to.
+	// It is implemented as a field so that it can be updated
+	// by tests.
+	replenish func(n int)
+}
+
+func newWriteQuota(sz int32, done <-chan struct{}) *writeQuota {
+	w := &writeQuota{
+		quota: sz,
+		ch:    make(chan struct{}, 1),
+		done:  done,
+	}
+	w.replenish = w.realReplenish
+	return w
 }
 
-func (*ping) item() {}
-
-// quotaPool is a pool which accumulates the quota and sends it to acquire()
-// when it is available.
-type quotaPool struct {
-	c chan int
-
-	mu      sync.Mutex
-	version uint32
-	quota   int
+func (w *writeQuota) get(sz int32) error {
+	for {
+		if atomic.LoadInt32(&w.quota) > 0 {
+			atomic.AddInt32(&w.quota, -sz)
+			return nil
+		}
+		select {
+		case <-w.ch:
+			continue
+		case <-w.done:
+			return errStreamDone
+		}
+	}
 }
 
-// newQuotaPool creates a quotaPool which has quota q available to consume.
-func newQuotaPool(q int) *quotaPool {
-	qb := &quotaPool{
-		c: make(chan int, 1),
-	}
-	if q > 0 {
-		qb.c <- q
-	} else {
-		qb.quota = q
+func (w *writeQuota) realReplenish(n int) {
+	sz := int32(n)
+	a := atomic.AddInt32(&w.quota, sz)
+	b := a - sz
+	if b <= 0 && a > 0 {
+		select {
+		case w.ch <- struct{}{}:
+		default:
+		}
 	}
-	return qb
 }
 
-// add cancels the pending quota sent on acquired, incremented by v and sends
-// it back on acquire.
-func (qb *quotaPool) add(v int) {
-	qb.mu.Lock()
-	defer qb.mu.Unlock()
-	qb.lockedAdd(v)
+type trInFlow struct {
+	limit               uint32
+	unacked             uint32
+	effectiveWindowSize uint32
 }
 
-func (qb *quotaPool) lockedAdd(v int) {
-	select {
-	case n := <-qb.c:
-		qb.quota += n
-	default:
-	}
-	qb.quota += v
-	if qb.quota <= 0 {
-		return
-	}
-	// After the pool has been created, this is the only place that sends on
-	// the channel. Since mu is held at this point and any quota that was sent
-	// on the channel has been retrieved, we know that this code will always
-	// place any positive quota value on the channel.
-	select {
-	case qb.c <- qb.quota:
-		qb.quota = 0
-	default:
-	}
+func (f *trInFlow) newLimit(n uint32) uint32 {
+	d := n - f.limit
+	f.limit = n
+	f.updateEffectiveWindowSize()
+	return d
 }
 
-func (qb *quotaPool) addAndUpdate(v int) {
-	qb.mu.Lock()
-	defer qb.mu.Unlock()
-	qb.lockedAdd(v)
-	// Update the version only after having added to the quota
-	// so that if acquireWithVesrion sees the new vesrion it is
-	// guaranteed to have seen the updated quota.
-	// Also, still keep this inside of the lock, so that when
-	// compareAndExecute is processing, this function doesn't
-	// get executed partially (quota gets updated but the version
-	// doesn't).
-	atomic.AddUint32(&(qb.version), 1)
+func (f *trInFlow) onData(n uint32) uint32 {
+	f.unacked += n
+	if f.unacked >= f.limit/4 {
+		w := f.unacked
+		f.unacked = 0
+		f.updateEffectiveWindowSize()
+		return w
+	}
+	f.updateEffectiveWindowSize()
+	return 0
 }
 
-func (qb *quotaPool) acquireWithVersion() (<-chan int, uint32) {
-	return qb.c, atomic.LoadUint32(&(qb.version))
+func (f *trInFlow) reset() uint32 {
+	w := f.unacked
+	f.unacked = 0
+	f.updateEffectiveWindowSize()
+	return w
 }
 
-func (qb *quotaPool) compareAndExecute(version uint32, success, failure func()) bool {
-	qb.mu.Lock()
-	defer qb.mu.Unlock()
-	if version == atomic.LoadUint32(&(qb.version)) {
-		success()
-		return true
-	}
-	failure()
-	return false
+func (f *trInFlow) updateEffectiveWindowSize() {
+	atomic.StoreUint32(&f.effectiveWindowSize, f.limit-f.unacked)
 }
 
-// acquire returns the channel on which available quota amounts are sent.
-func (qb *quotaPool) acquire() <-chan int {
-	return qb.c
+func (f *trInFlow) getSize() uint32 {
+	return atomic.LoadUint32(&f.effectiveWindowSize)
 }
 
+// TODO(mmukhi): Simplify this code.
 // inFlow deals with inbound flow control
 type inFlow struct {
 	mu sync.Mutex
@@ -229,9 +162,9 @@ type inFlow struct {
 // It assumes that n is always greater than the old limit.
 func (f *inFlow) newLimit(n uint32) uint32 {
 	f.mu.Lock()
-	defer f.mu.Unlock()
 	d := n - f.limit
 	f.limit = n
+	f.mu.Unlock()
 	return d
 }
 
@@ -240,7 +173,6 @@ func (f *inFlow) maybeAdjust(n uint32) uint32 {
 		n = uint32(math.MaxInt32)
 	}
 	f.mu.Lock()
-	defer f.mu.Unlock()
 	// estSenderQuota is the receiver's view of the maximum number of bytes the sender
 	// can send without a window update.
 	estSenderQuota := int32(f.limit - (f.pendingData + f.pendingUpdate))
@@ -252,7 +184,7 @@ func (f *inFlow) maybeAdjust(n uint32) uint32 {
 	// for this message. Therefore we must send an update over the limit since there's an active read
 	// request from the application.
 	if estUntransmittedData > estSenderQuota {
-		// Sender's window shouldn't go more than 2^31 - 1 as speecified in the HTTP spec.
+		// Sender's window shouldn't go more than 2^31 - 1 as specified in the HTTP spec.
 		if f.limit+n > maxWindowSize {
 			f.delta = maxWindowSize - f.limit
 		} else {
@@ -261,19 +193,24 @@ func (f *inFlow) maybeAdjust(n uint32) uint32 {
 			// is padded; We will fallback on the current available window(at least a 1/4th of the limit).
 			f.delta = n
 		}
+		f.mu.Unlock()
 		return f.delta
 	}
+	f.mu.Unlock()
 	return 0
 }
 
 // onData is invoked when some data frame is received. It updates pendingData.
 func (f *inFlow) onData(n uint32) error {
 	f.mu.Lock()
-	defer f.mu.Unlock()
 	f.pendingData += n
 	if f.pendingData+f.pendingUpdate > f.limit+f.delta {
-		return fmt.Errorf("received %d-bytes data exceeding the limit %d bytes", f.pendingData+f.pendingUpdate, f.limit)
+		limit := f.limit
+		rcvd := f.pendingData + f.pendingUpdate
+		f.mu.Unlock()
+		return fmt.Errorf("received %d-bytes data exceeding the limit %d bytes", rcvd, limit)
 	}
+	f.mu.Unlock()
 	return nil
 }
 
@@ -281,8 +218,8 @@ func (f *inFlow) onData(n uint32) error {
 // to be sent to the peer.
 func (f *inFlow) onRead(n uint32) uint32 {
 	f.mu.Lock()
-	defer f.mu.Unlock()
 	if f.pendingData == 0 {
+		f.mu.Unlock()
 		return 0
 	}
 	f.pendingData -= n
@@ -297,15 +234,9 @@ func (f *inFlow) onRead(n uint32) uint32 {
 	if f.pendingUpdate >= f.limit/4 {
 		wu := f.pendingUpdate
 		f.pendingUpdate = 0
+		f.mu.Unlock()
 		return wu
 	}
+	f.mu.Unlock()
 	return 0
 }
-
-func (f *inFlow) resetPendingUpdate() uint32 {
-	f.mu.Lock()
-	defer f.mu.Unlock()
-	n := f.pendingUpdate
-	f.pendingUpdate = 0
-	return n
-}
diff --git a/vendor/google.golang.org/grpc/transport/go16.go b/vendor/google.golang.org/grpc/transport/go16.go
new file mode 100644
index 0000000..5babcf9
--- /dev/null
+++ b/vendor/google.golang.org/grpc/transport/go16.go
@@ -0,0 +1,51 @@
+// +build go1.6,!go1.7
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package transport
+
+import (
+	"net"
+	"net/http"
+
+	"google.golang.org/grpc/codes"
+
+	"golang.org/x/net/context"
+)
+
+// dialContext connects to the address on the named network.
+func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return (&net.Dialer{Cancel: ctx.Done()}).Dial(network, address)
+}
+
+// ContextErr converts the error from context package into a StreamError.
+func ContextErr(err error) StreamError {
+	switch err {
+	case context.DeadlineExceeded:
+		return streamErrorf(codes.DeadlineExceeded, "%v", err)
+	case context.Canceled:
+		return streamErrorf(codes.Canceled, "%v", err)
+	}
+	return streamErrorf(codes.Internal, "Unexpected error from context packet: %v", err)
+}
+
+// contextFromRequest returns a background context.
+func contextFromRequest(r *http.Request) context.Context {
+	return context.Background()
+}
diff --git a/vendor/google.golang.org/grpc/transport/go17.go b/vendor/google.golang.org/grpc/transport/go17.go
new file mode 100644
index 0000000..b7fa6bd
--- /dev/null
+++ b/vendor/google.golang.org/grpc/transport/go17.go
@@ -0,0 +1,52 @@
+// +build go1.7
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package transport
+
+import (
+	"context"
+	"net"
+	"net/http"
+
+	"google.golang.org/grpc/codes"
+
+	netctx "golang.org/x/net/context"
+)
+
+// dialContext connects to the address on the named network.
+func dialContext(ctx context.Context, network, address string) (net.Conn, error) {
+	return (&net.Dialer{}).DialContext(ctx, network, address)
+}
+
+// ContextErr converts the error from context package into a StreamError.
+func ContextErr(err error) StreamError {
+	switch err {
+	case context.DeadlineExceeded, netctx.DeadlineExceeded:
+		return streamErrorf(codes.DeadlineExceeded, "%v", err)
+	case context.Canceled, netctx.Canceled:
+		return streamErrorf(codes.Canceled, "%v", err)
+	}
+	return streamErrorf(codes.Internal, "Unexpected error from context packet: %v", err)
+}
+
+// contextFromRequest returns a context from the HTTP Request.
+func contextFromRequest(r *http.Request) context.Context {
+	return r.Context()
+}
diff --git a/vendor/google.golang.org/grpc/transport/handler_server.go b/vendor/google.golang.org/grpc/transport/handler_server.go
index f1f6caf..f71b748 100644
--- a/vendor/google.golang.org/grpc/transport/handler_server.go
+++ b/vendor/google.golang.org/grpc/transport/handler_server.go
@@ -40,20 +40,24 @@ import (
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/peer"
+	"google.golang.org/grpc/stats"
 	"google.golang.org/grpc/status"
 )
 
 // NewServerHandlerTransport returns a ServerTransport handling gRPC
 // from inside an http.Handler. It requires that the http Server
 // supports HTTP/2.
-func NewServerHandlerTransport(w http.ResponseWriter, r *http.Request) (ServerTransport, error) {
+func NewServerHandlerTransport(w http.ResponseWriter, r *http.Request, stats stats.Handler) (ServerTransport, error) {
 	if r.ProtoMajor != 2 {
 		return nil, errors.New("gRPC requires HTTP/2")
 	}
 	if r.Method != "POST" {
 		return nil, errors.New("invalid gRPC request method")
 	}
-	if !validContentType(r.Header.Get("Content-Type")) {
+	contentType := r.Header.Get("Content-Type")
+	// TODO: do we assume contentType is lowercase? we did before
+	contentSubtype, validContentType := contentSubtype(contentType)
+	if !validContentType {
 		return nil, errors.New("invalid gRPC request content-type")
 	}
 	if _, ok := w.(http.Flusher); !ok {
@@ -64,10 +68,13 @@ func NewServerHandlerTransport(w http.ResponseWriter, r *http.Request) (ServerTr
 	}
 
 	st := &serverHandlerTransport{
-		rw:       w,
-		req:      r,
-		closedCh: make(chan struct{}),
-		writes:   make(chan func()),
+		rw:             w,
+		req:            r,
+		closedCh:       make(chan struct{}),
+		writes:         make(chan func()),
+		contentType:    contentType,
+		contentSubtype: contentSubtype,
+		stats:          stats,
 	}
 
 	if v := r.Header.Get("grpc-timeout"); v != "" {
@@ -79,19 +86,19 @@ func NewServerHandlerTransport(w http.ResponseWriter, r *http.Request) (ServerTr
 		st.timeout = to
 	}
 
-	var metakv []string
+	metakv := []string{"content-type", contentType}
 	if r.Host != "" {
 		metakv = append(metakv, ":authority", r.Host)
 	}
 	for k, vv := range r.Header {
 		k = strings.ToLower(k)
-		if isReservedHeader(k) && !isWhitelistedPseudoHeader(k) {
+		if isReservedHeader(k) && !isWhitelistedHeader(k) {
 			continue
 		}
 		for _, v := range vv {
 			v, err := decodeMetadataHeader(k, v)
 			if err != nil {
-				return nil, streamErrorf(codes.InvalidArgument, "malformed binary metadata: %v", err)
+				return nil, streamErrorf(codes.Internal, "malformed binary metadata: %v", err)
 			}
 			metakv = append(metakv, k, v)
 		}
@@ -123,10 +130,17 @@ type serverHandlerTransport struct {
 	// when WriteStatus is called.
 	writes chan func()
 
-	mu sync.Mutex
-	// streamDone indicates whether WriteStatus has been called and writes channel
-	// has been closed.
-	streamDone bool
+	// block concurrent WriteStatus calls
+	// e.g. grpc/(*serverStream).SendMsg/RecvMsg
+	writeStatusMu sync.Mutex
+
+	// we just mirror the request content-type
+	contentType string
+	// we store both contentType and contentSubtype so we don't keep recreating them
+	// TODO make sure this is consistent across handler_server and http2_server
+	contentSubtype string
+
+	stats stats.Handler
 }
 
 func (ht *serverHandlerTransport) Close() error {
@@ -177,13 +191,9 @@ func (ht *serverHandlerTransport) do(fn func()) error {
 }
 
 func (ht *serverHandlerTransport) WriteStatus(s *Stream, st *status.Status) error {
-	ht.mu.Lock()
-	if ht.streamDone {
-		ht.mu.Unlock()
-		return nil
-	}
-	ht.streamDone = true
-	ht.mu.Unlock()
+	ht.writeStatusMu.Lock()
+	defer ht.writeStatusMu.Unlock()
+
 	err := ht.do(func() {
 		ht.writeCommonHeaders(s)
 
@@ -222,7 +232,14 @@ func (ht *serverHandlerTransport) WriteStatus(s *Stream, st *status.Status) erro
 			}
 		}
 	})
-	close(ht.writes)
+
+	if err == nil { // transport has not been closed
+		if ht.stats != nil {
+			ht.stats.HandleRPC(s.Context(), &stats.OutTrailer{})
+		}
+		ht.Close()
+		close(ht.writes)
+	}
 	return err
 }
 
@@ -236,7 +253,7 @@ func (ht *serverHandlerTransport) writeCommonHeaders(s *Stream) {
 
 	h := ht.rw.Header()
 	h["Date"] = nil // suppress Date to make tests happy; TODO: restore
-	h.Set("Content-Type", "application/grpc")
+	h.Set("Content-Type", ht.contentType)
 
 	// Predeclare trailers we'll set later in WriteStatus (after the body).
 	// This is a SHOULD in the HTTP RFC, and the way you add (known)
@@ -264,7 +281,7 @@ func (ht *serverHandlerTransport) Write(s *Stream, hdr []byte, data []byte, opts
 }
 
 func (ht *serverHandlerTransport) WriteHeader(s *Stream, md metadata.MD) error {
-	return ht.do(func() {
+	err := ht.do(func() {
 		ht.writeCommonHeaders(s)
 		h := ht.rw.Header()
 		for k, vv := range md {
@@ -280,17 +297,24 @@ func (ht *serverHandlerTransport) WriteHeader(s *Stream, md metadata.MD) error {
 		ht.rw.WriteHeader(200)
 		ht.rw.(http.Flusher).Flush()
 	})
+
+	if err == nil {
+		if ht.stats != nil {
+			ht.stats.HandleRPC(s.Context(), &stats.OutHeader{})
+		}
+	}
+	return err
 }
 
 func (ht *serverHandlerTransport) HandleStreams(startStream func(*Stream), traceCtx func(context.Context, string) context.Context) {
 	// With this transport type there will be exactly 1 stream: this HTTP request.
 
-	var ctx context.Context
+	ctx := contextFromRequest(ht.req)
 	var cancel context.CancelFunc
 	if ht.timeoutSet {
-		ctx, cancel = context.WithTimeout(context.Background(), ht.timeout)
+		ctx, cancel = context.WithTimeout(ctx, ht.timeout)
 	} else {
-		ctx, cancel = context.WithCancel(context.Background())
+		ctx, cancel = context.WithCancel(ctx)
 	}
 
 	// requestOver is closed when either the request's context is done
@@ -314,13 +338,14 @@ func (ht *serverHandlerTransport) HandleStreams(startStream func(*Stream), trace
 	req := ht.req
 
 	s := &Stream{
-		id:           0, // irrelevant
-		requestRead:  func(int) {},
-		cancel:       cancel,
-		buf:          newRecvBuffer(),
-		st:           ht,
-		method:       req.URL.Path,
-		recvCompress: req.Header.Get("grpc-encoding"),
+		id:             0, // irrelevant
+		requestRead:    func(int) {},
+		cancel:         cancel,
+		buf:            newRecvBuffer(),
+		st:             ht,
+		method:         req.URL.Path,
+		recvCompress:   req.Header.Get("grpc-encoding"),
+		contentSubtype: ht.contentSubtype,
 	}
 	pr := &peer.Peer{
 		Addr: ht.RemoteAddr(),
@@ -329,10 +354,18 @@ func (ht *serverHandlerTransport) HandleStreams(startStream func(*Stream), trace
 		pr.AuthInfo = credentials.TLSInfo{State: *req.TLS}
 	}
 	ctx = metadata.NewIncomingContext(ctx, ht.headerMD)
-	ctx = peer.NewContext(ctx, pr)
-	s.ctx = newContextWithStream(ctx, s)
+	s.ctx = peer.NewContext(ctx, pr)
+	if ht.stats != nil {
+		s.ctx = ht.stats.TagRPC(s.ctx, &stats.RPCTagInfo{FullMethodName: s.method})
+		inHeader := &stats.InHeader{
+			FullMethod:  s.method,
+			RemoteAddr:  ht.RemoteAddr(),
+			Compression: s.recvCompress,
+		}
+		ht.stats.HandleRPC(s.ctx, inHeader)
+	}
 	s.trReader = &transportReader{
-		reader:        &recvBufferReader{ctx: s.ctx, recv: s.buf},
+		reader:        &recvBufferReader{ctx: s.ctx, ctxDone: s.ctx.Done(), recv: s.buf},
 		windowHandler: func(int) {},
 	}
 
@@ -387,6 +420,10 @@ func (ht *serverHandlerTransport) runStream() {
 	}
 }
 
+func (ht *serverHandlerTransport) IncrMsgSent() {}
+
+func (ht *serverHandlerTransport) IncrMsgRecv() {}
+
 func (ht *serverHandlerTransport) Drain() {
 	panic("Drain() is not implemented")
 }
diff --git a/vendor/google.golang.org/grpc/transport/http2_client.go b/vendor/google.golang.org/grpc/transport/http2_client.go
index 6ca6cc6..eaf007e 100644
--- a/vendor/google.golang.org/grpc/transport/http2_client.go
+++ b/vendor/google.golang.org/grpc/transport/http2_client.go
@@ -19,7 +19,6 @@
 package transport
 
 import (
-	"bytes"
 	"io"
 	"math"
 	"net"
@@ -31,8 +30,10 @@ import (
 	"golang.org/x/net/context"
 	"golang.org/x/net/http2"
 	"golang.org/x/net/http2/hpack"
+
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/peer"
@@ -44,15 +45,17 @@ import (
 type http2Client struct {
 	ctx        context.Context
 	cancel     context.CancelFunc
-	target     string // server name/addr
+	ctxDone    <-chan struct{} // Cache the ctx.Done() chan.
 	userAgent  string
 	md         interface{}
 	conn       net.Conn // underlying communication channel
+	loopy      *loopyWriter
 	remoteAddr net.Addr
 	localAddr  net.Addr
 	authInfo   credentials.AuthInfo // auth info about the connection
-	nextID     uint32               // the next stream ID to be used
 
+	readerDone chan struct{} // sync point to enable testing.
+	writerDone chan struct{} // sync point to enable testing.
 	// goAway is closed to notify the upper layer (i.e., addrConn.transportMonitor)
 	// that the server sent GoAway on this transport.
 	goAway chan struct{}
@@ -60,18 +63,10 @@ type http2Client struct {
 	awakenKeepalive chan struct{}
 
 	framer *framer
-	hBuf   *bytes.Buffer  // the buffer for HPACK encoding
-	hEnc   *hpack.Encoder // HPACK encoder
-
 	// controlBuf delivers all the control related tasks (e.g., window
 	// updates, reset streams, and various settings) to the controller.
 	controlBuf *controlBuffer
-	fc         *inFlow
-	// sendQuotaPool provides flow control to outbound message.
-	sendQuotaPool *quotaPool
-	// streamsQuota limits the max number of concurrent streams.
-	streamsQuota *quotaPool
-
+	fc         *trInFlow
 	// The scheme used: https if TLS is on, http otherwise.
 	scheme string
 
@@ -81,50 +76,60 @@ type http2Client struct {
 
 	// Boolean to keep track of reading activity on transport.
 	// 1 is true and 0 is false.
-	activity uint32 // Accessed atomically.
-	kp       keepalive.ClientParameters
+	activity         uint32 // Accessed atomically.
+	kp               keepalive.ClientParameters
+	keepaliveEnabled bool
 
 	statsHandler stats.Handler
 
 	initialWindowSize int32
 
-	bdpEst          *bdpEstimator
-	outQuotaVersion uint32
+	bdpEst *bdpEstimator
+	// onSuccess is a callback that client transport calls upon
+	// receiving server preface to signal that a succefull HTTP2
+	// connection was established.
+	onSuccess func()
 
-	mu            sync.Mutex     // guard the following variables
-	state         transportState // the state of underlying connection
+	maxConcurrentStreams  uint32
+	streamQuota           int64
+	streamsQuotaAvailable chan struct{}
+	waitingStreams        uint32
+	nextID                uint32
+
+	mu            sync.Mutex // guard the following variables
+	state         transportState
 	activeStreams map[uint32]*Stream
-	// The max number of concurrent streams
-	maxStreams int
-	// the per-stream outbound flow control window size set by the peer.
-	streamSendQuota uint32
 	// prevGoAway ID records the Last-Stream-ID in the previous GOAway frame.
 	prevGoAwayID uint32
 	// goAwayReason records the http2.ErrCode and debug data received with the
 	// GoAway frame.
 	goAwayReason GoAwayReason
+
+	// Fields below are for channelz metric collection.
+	channelzID int64 // channelz unique identification number
+	czmu       sync.RWMutex
+	kpCount    int64
+	// The number of streams that have started, including already finished ones.
+	streamsStarted int64
+	// The number of streams that have ended successfully by receiving EoS bit set
+	// frame from server.
+	streamsSucceeded  int64
+	streamsFailed     int64
+	lastStreamCreated time.Time
+	msgSent           int64
+	msgRecv           int64
+	lastMsgSent       time.Time
+	lastMsgRecv       time.Time
 }
 
 func dial(ctx context.Context, fn func(context.Context, string) (net.Conn, error), addr string) (net.Conn, error) {
 	if fn != nil {
 		return fn(ctx, addr)
 	}
-	return (&net.Dialer{}).DialContext(ctx, "tcp", addr)
+	return dialContext(ctx, "tcp", addr)
 }
 
 func isTemporary(err error) bool {
-	switch err {
-	case io.EOF:
-		// Connection closures may be resolved upon retry, and are thus
-		// treated as temporary.
-		return true
-	case context.DeadlineExceeded:
-		// In Go 1.7, context.DeadlineExceeded implements Timeout(), and this
-		// special case is not needed. Until then, we need to keep this
-		// clause.
-		return true
-	}
-
 	switch err := err.(type) {
 	case interface {
 		Temporary() bool
@@ -137,18 +142,16 @@ func isTemporary(err error) bool {
 		// temporary.
 		return err.Timeout()
 	}
-	return false
+	return true
 }
 
 // newHTTP2Client constructs a connected ClientTransport to addr based on HTTP2
 // and starts to receive messages on it. Non-nil error returns if construction
 // fails.
-func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions, timeout time.Duration) (_ ClientTransport, err error) {
+func newHTTP2Client(connectCtx, ctx context.Context, addr TargetInfo, opts ConnectOptions, onSuccess func()) (_ ClientTransport, err error) {
 	scheme := "http"
 	ctx, cancel := context.WithCancel(ctx)
-	connectCtx, connectCancel := context.WithTimeout(ctx, timeout)
 	defer func() {
-		connectCancel()
 		if err != nil {
 			cancel()
 		}
@@ -173,12 +176,9 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions, t
 	)
 	if creds := opts.TransportCredentials; creds != nil {
 		scheme = "https"
-		conn, authInfo, err = creds.ClientHandshake(connectCtx, addr.Addr, conn)
+		conn, authInfo, err = creds.ClientHandshake(connectCtx, addr.Authority, conn)
 		if err != nil {
-			// Credentials handshake errors are typically considered permanent
-			// to avoid retrying on e.g. bad certificates.
-			temp := isTemporary(err)
-			return nil, connectionErrorf(temp, err, "transport: authentication handshake failed: %v", err)
+			return nil, connectionErrorf(isTemporary(err), err, "transport: authentication handshake failed: %v", err)
 		}
 		isSecure = true
 	}
@@ -196,7 +196,6 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions, t
 		icwz = opts.InitialConnWindowSize
 		dynamicWindow = false
 	}
-	var buf bytes.Buffer
 	writeBufSize := defaultWriteBufSize
 	if opts.WriteBufferSize > 0 {
 		writeBufSize = opts.WriteBufferSize
@@ -206,37 +205,35 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions, t
 		readBufSize = opts.ReadBufferSize
 	}
 	t := &http2Client{
-		ctx:        ctx,
-		cancel:     cancel,
-		target:     addr.Addr,
-		userAgent:  opts.UserAgent,
-		md:         addr.Metadata,
-		conn:       conn,
-		remoteAddr: conn.RemoteAddr(),
-		localAddr:  conn.LocalAddr(),
-		authInfo:   authInfo,
-		// The client initiated stream id is odd starting from 1.
-		nextID:            1,
-		goAway:            make(chan struct{}),
-		awakenKeepalive:   make(chan struct{}, 1),
-		hBuf:              &buf,
-		hEnc:              hpack.NewEncoder(&buf),
-		framer:            newFramer(conn, writeBufSize, readBufSize),
-		controlBuf:        newControlBuffer(),
-		fc:                &inFlow{limit: uint32(icwz)},
-		sendQuotaPool:     newQuotaPool(defaultWindowSize),
-		scheme:            scheme,
-		state:             reachable,
-		activeStreams:     make(map[uint32]*Stream),
-		isSecure:          isSecure,
-		creds:             opts.PerRPCCredentials,
-		maxStreams:        defaultMaxStreamsClient,
-		streamsQuota:      newQuotaPool(defaultMaxStreamsClient),
-		streamSendQuota:   defaultWindowSize,
-		kp:                kp,
-		statsHandler:      opts.StatsHandler,
-		initialWindowSize: initialWindowSize,
-	}
+		ctx:                   ctx,
+		ctxDone:               ctx.Done(), // Cache Done chan.
+		cancel:                cancel,
+		userAgent:             opts.UserAgent,
+		md:                    addr.Metadata,
+		conn:                  conn,
+		remoteAddr:            conn.RemoteAddr(),
+		localAddr:             conn.LocalAddr(),
+		authInfo:              authInfo,
+		readerDone:            make(chan struct{}),
+		writerDone:            make(chan struct{}),
+		goAway:                make(chan struct{}),
+		awakenKeepalive:       make(chan struct{}, 1),
+		framer:                newFramer(conn, writeBufSize, readBufSize),
+		fc:                    &trInFlow{limit: uint32(icwz)},
+		scheme:                scheme,
+		activeStreams:         make(map[uint32]*Stream),
+		isSecure:              isSecure,
+		creds:                 opts.PerRPCCredentials,
+		kp:                    kp,
+		statsHandler:          opts.StatsHandler,
+		initialWindowSize:     initialWindowSize,
+		onSuccess:             onSuccess,
+		nextID:                1,
+		maxConcurrentStreams:  defaultMaxStreamsClient,
+		streamQuota:           defaultMaxStreamsClient,
+		streamsQuotaAvailable: make(chan struct{}, 1),
+	}
+	t.controlBuf = newControlBuffer(t.ctxDone)
 	if opts.InitialWindowSize >= defaultWindowSize {
 		t.initialWindowSize = opts.InitialWindowSize
 		dynamicWindow = false
@@ -260,6 +257,13 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions, t
 		}
 		t.statsHandler.HandleConn(t.ctx, connBegin)
 	}
+	if channelz.IsOn() {
+		t.channelzID = channelz.RegisterNormalSocket(t, opts.ChannelzParentID, "")
+	}
+	if t.kp.Time != infinity {
+		t.keepaliveEnabled = true
+		go t.keepalive()
+	}
 	// Start the reader goroutine for incoming message. Each transport has
 	// a dedicated goroutine which reads HTTP2 frame from network. Then it
 	// dispatches the frame to the corresponding stream entity.
@@ -295,30 +299,32 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions, t
 	}
 	t.framer.writer.Flush()
 	go func() {
-		loopyWriter(t.ctx, t.controlBuf, t.itemHandler)
-		t.Close()
+		t.loopy = newLoopyWriter(clientSide, t.framer, t.controlBuf, t.bdpEst)
+		err := t.loopy.run()
+		if err != nil {
+			errorf("transport: loopyWriter.run returning. Err: %v", err)
+		}
+		// If it's a connection error, let reader goroutine handle it
+		// since there might be data in the buffers.
+		if _, ok := err.(net.Error); !ok {
+			t.conn.Close()
+		}
+		close(t.writerDone)
 	}()
-	if t.kp.Time != infinity {
-		go t.keepalive()
-	}
 	return t, nil
 }
 
 func (t *http2Client) newStream(ctx context.Context, callHdr *CallHdr) *Stream {
 	// TODO(zhaoq): Handle uint32 overflow of Stream.id.
 	s := &Stream{
-		id:             t.nextID,
 		done:           make(chan struct{}),
-		goAway:         make(chan struct{}),
 		method:         callHdr.Method,
 		sendCompress:   callHdr.SendCompress,
 		buf:            newRecvBuffer(),
-		fc:             &inFlow{limit: uint32(t.initialWindowSize)},
-		sendQuotaPool:  newQuotaPool(int(t.streamSendQuota)),
-		localSendQuota: newQuotaPool(defaultLocalSendQuota),
 		headerChan:     make(chan struct{}),
+		contentSubtype: callHdr.ContentSubtype,
 	}
-	t.nextID += 2
+	s.wq = newWriteQuota(defaultWriteQuota, s.done)
 	s.requestRead = func(n int) {
 		t.adjustWindow(s, uint32(n))
 	}
@@ -328,21 +334,18 @@ func (t *http2Client) newStream(ctx context.Context, callHdr *CallHdr) *Stream {
 	s.ctx = ctx
 	s.trReader = &transportReader{
 		reader: &recvBufferReader{
-			ctx:    s.ctx,
-			goAway: s.goAway,
-			recv:   s.buf,
+			ctx:     s.ctx,
+			ctxDone: s.ctx.Done(),
+			recv:    s.buf,
 		},
 		windowHandler: func(n int) {
 			t.updateWindow(s, uint32(n))
 		},
 	}
-
 	return s
 }
 
-// NewStream creates a stream and registers it into the transport as "active"
-// streams.
-func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Stream, err error) {
+func (t *http2Client) getPeer() *peer.Peer {
 	pr := &peer.Peer{
 		Addr: t.remoteAddr,
 	}
@@ -350,74 +353,20 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 	if t.authInfo != nil {
 		pr.AuthInfo = t.authInfo
 	}
-	ctx = peer.NewContext(ctx, pr)
-	var (
-		authData = make(map[string]string)
-		audience string
-	)
-	// Create an audience string only if needed.
-	if len(t.creds) > 0 || callHdr.Creds != nil {
-		// Construct URI required to get auth request metadata.
-		// Omit port if it is the default one.
-		host := strings.TrimSuffix(callHdr.Host, ":443")
-		pos := strings.LastIndex(callHdr.Method, "/")
-		if pos == -1 {
-			pos = len(callHdr.Method)
-		}
-		audience = "https://" + host + callHdr.Method[:pos]
-	}
-	for _, c := range t.creds {
-		data, err := c.GetRequestMetadata(ctx, audience)
-		if err != nil {
-			return nil, streamErrorf(codes.Internal, "transport: %v", err)
-		}
-		for k, v := range data {
-			// Capital header names are illegal in HTTP/2.
-			k = strings.ToLower(k)
-			authData[k] = v
-		}
-	}
-	callAuthData := map[string]string{}
-	// Check if credentials.PerRPCCredentials were provided via call options.
-	// Note: if these credentials are provided both via dial options and call
-	// options, then both sets of credentials will be applied.
-	if callCreds := callHdr.Creds; callCreds != nil {
-		if !t.isSecure && callCreds.RequireTransportSecurity() {
-			return nil, streamErrorf(codes.Unauthenticated, "transport: cannot send secure credentials on an insecure connection")
-		}
-		data, err := callCreds.GetRequestMetadata(ctx, audience)
-		if err != nil {
-			return nil, streamErrorf(codes.Internal, "transport: %v", err)
-		}
-		for k, v := range data {
-			// Capital header names are illegal in HTTP/2
-			k = strings.ToLower(k)
-			callAuthData[k] = v
-		}
-	}
-	t.mu.Lock()
-	if t.activeStreams == nil {
-		t.mu.Unlock()
-		return nil, ErrConnClosing
-	}
-	if t.state == draining {
-		t.mu.Unlock()
-		return nil, ErrStreamDrain
-	}
-	if t.state != reachable {
-		t.mu.Unlock()
-		return nil, ErrConnClosing
-	}
-	t.mu.Unlock()
-	sq, err := wait(ctx, t.ctx, nil, nil, t.streamsQuota.acquire())
+	return pr
+}
+
+func (t *http2Client) createHeaderFields(ctx context.Context, callHdr *CallHdr) ([]hpack.HeaderField, error) {
+	aud := t.createAudience(callHdr)
+	authData, err := t.getTrAuthData(ctx, aud)
 	if err != nil {
 		return nil, err
 	}
-	// Returns the quota balance back.
-	if sq > 1 {
-		t.streamsQuota.add(sq - 1)
+	callAuthData, err := t.getCallAuthData(ctx, aud, callHdr)
+	if err != nil {
+		return nil, err
 	}
-	// TODO(mmukhi): Benchmark if the perfomance gets better if count the metadata and other header fields
+	// TODO(mmukhi): Benchmark if the performance gets better if count the metadata and other header fields
 	// first and create a slice of that exact size.
 	// Make the slice of certain predictable size to reduce allocations made by append.
 	hfLen := 7 // :method, :scheme, :path, :authority, content-type, user-agent, te
@@ -427,7 +376,7 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 	headerFields = append(headerFields, hpack.HeaderField{Name: ":scheme", Value: t.scheme})
 	headerFields = append(headerFields, hpack.HeaderField{Name: ":path", Value: callHdr.Method})
 	headerFields = append(headerFields, hpack.HeaderField{Name: ":authority", Value: callHdr.Host})
-	headerFields = append(headerFields, hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
+	headerFields = append(headerFields, hpack.HeaderField{Name: "content-type", Value: contentType(callHdr.ContentSubtype)})
 	headerFields = append(headerFields, hpack.HeaderField{Name: "user-agent", Value: t.userAgent})
 	headerFields = append(headerFields, hpack.HeaderField{Name: "te", Value: "trailers"})
 
@@ -452,7 +401,22 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 	if b := stats.OutgoingTrace(ctx); b != nil {
 		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-trace-bin", Value: encodeBinHeader(b)})
 	}
-	if md, ok := metadata.FromOutgoingContext(ctx); ok {
+
+	if md, added, ok := metadata.FromOutgoingContextRaw(ctx); ok {
+		var k string
+		for _, vv := range added {
+			for i, v := range vv {
+				if i%2 == 0 {
+					k = v
+					continue
+				}
+				// HTTP doesn't allow you to set pseudoheaders after non pseudoheaders were set.
+				if isReservedHeader(k) {
+					continue
+				}
+				headerFields = append(headerFields, hpack.HeaderField{Name: strings.ToLower(k), Value: encodeMetadataHeader(k, v)})
+			}
+		}
 		for k, vv := range md {
 			// HTTP doesn't allow you to set pseudoheaders after non pseudoheaders were set.
 			if isReservedHeader(k) {
@@ -473,42 +437,178 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 			}
 		}
 	}
-	t.mu.Lock()
-	if t.state == draining {
-		t.mu.Unlock()
-		t.streamsQuota.add(1)
-		return nil, ErrStreamDrain
+	return headerFields, nil
+}
+
+func (t *http2Client) createAudience(callHdr *CallHdr) string {
+	// Create an audience string only if needed.
+	if len(t.creds) == 0 && callHdr.Creds == nil {
+		return ""
 	}
-	if t.state != reachable {
-		t.mu.Unlock()
-		return nil, ErrConnClosing
+	// Construct URI required to get auth request metadata.
+	// Omit port if it is the default one.
+	host := strings.TrimSuffix(callHdr.Host, ":443")
+	pos := strings.LastIndex(callHdr.Method, "/")
+	if pos == -1 {
+		pos = len(callHdr.Method)
+	}
+	return "https://" + host + callHdr.Method[:pos]
+}
+
+func (t *http2Client) getTrAuthData(ctx context.Context, audience string) (map[string]string, error) {
+	authData := map[string]string{}
+	for _, c := range t.creds {
+		data, err := c.GetRequestMetadata(ctx, audience)
+		if err != nil {
+			if _, ok := status.FromError(err); ok {
+				return nil, err
+			}
+
+			return nil, streamErrorf(codes.Unauthenticated, "transport: %v", err)
+		}
+		for k, v := range data {
+			// Capital header names are illegal in HTTP/2.
+			k = strings.ToLower(k)
+			authData[k] = v
+		}
+	}
+	return authData, nil
+}
+
+func (t *http2Client) getCallAuthData(ctx context.Context, audience string, callHdr *CallHdr) (map[string]string, error) {
+	callAuthData := map[string]string{}
+	// Check if credentials.PerRPCCredentials were provided via call options.
+	// Note: if these credentials are provided both via dial options and call
+	// options, then both sets of credentials will be applied.
+	if callCreds := callHdr.Creds; callCreds != nil {
+		if !t.isSecure && callCreds.RequireTransportSecurity() {
+			return nil, streamErrorf(codes.Unauthenticated, "transport: cannot send secure credentials on an insecure connection")
+		}
+		data, err := callCreds.GetRequestMetadata(ctx, audience)
+		if err != nil {
+			return nil, streamErrorf(codes.Internal, "transport: %v", err)
+		}
+		for k, v := range data {
+			// Capital header names are illegal in HTTP/2
+			k = strings.ToLower(k)
+			callAuthData[k] = v
+		}
+	}
+	return callAuthData, nil
+}
+
+// NewStream creates a stream and registers it into the transport as "active"
+// streams.
+func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Stream, err error) {
+	ctx = peer.NewContext(ctx, t.getPeer())
+	headerFields, err := t.createHeaderFields(ctx, callHdr)
+	if err != nil {
+		return nil, err
 	}
 	s := t.newStream(ctx, callHdr)
-	t.activeStreams[s.id] = s
-	// If the number of active streams change from 0 to 1, then check if keepalive
-	// has gone dormant. If so, wake it up.
-	if len(t.activeStreams) == 1 {
-		select {
-		case t.awakenKeepalive <- struct{}{}:
-			t.controlBuf.put(&ping{data: [8]byte{}})
-			// Fill the awakenKeepalive channel again as this channel must be
-			// kept non-writable except at the point that the keepalive()
-			// goroutine is waiting either to be awaken or shutdown.
-			t.awakenKeepalive <- struct{}{}
-		default:
+	cleanup := func(err error) {
+		if s.swapState(streamDone) == streamDone {
+			// If it was already done, return.
+			return
+		}
+		// The stream was unprocessed by the server.
+		atomic.StoreUint32(&s.unprocessed, 1)
+		s.write(recvMsg{err: err})
+		close(s.done)
+		// If headerChan isn't closed, then close it.
+		if atomic.SwapUint32(&s.headerDone, 1) == 0 {
+			close(s.headerChan)
 		}
+
 	}
-	t.controlBuf.put(&headerFrame{
-		streamID:  s.id,
+	hdr := &headerFrame{
 		hf:        headerFields,
 		endStream: false,
-	})
-	t.mu.Unlock()
-
-	s.mu.Lock()
-	s.bytesSent = true
-	s.mu.Unlock()
-
+		initStream: func(id uint32) (bool, error) {
+			t.mu.Lock()
+			if state := t.state; state != reachable {
+				t.mu.Unlock()
+				// Do a quick cleanup.
+				err := error(errStreamDrain)
+				if state == closing {
+					err = ErrConnClosing
+				}
+				cleanup(err)
+				return false, err
+			}
+			t.activeStreams[id] = s
+			if channelz.IsOn() {
+				t.czmu.Lock()
+				t.streamsStarted++
+				t.lastStreamCreated = time.Now()
+				t.czmu.Unlock()
+			}
+			var sendPing bool
+			// If the number of active streams change from 0 to 1, then check if keepalive
+			// has gone dormant. If so, wake it up.
+			if len(t.activeStreams) == 1 && t.keepaliveEnabled {
+				select {
+				case t.awakenKeepalive <- struct{}{}:
+					sendPing = true
+					// Fill the awakenKeepalive channel again as this channel must be
+					// kept non-writable except at the point that the keepalive()
+					// goroutine is waiting either to be awaken or shutdown.
+					t.awakenKeepalive <- struct{}{}
+				default:
+				}
+			}
+			t.mu.Unlock()
+			return sendPing, nil
+		},
+		onOrphaned: cleanup,
+		wq:         s.wq,
+	}
+	firstTry := true
+	var ch chan struct{}
+	checkForStreamQuota := func(it interface{}) bool {
+		if t.streamQuota <= 0 { // Can go negative if server decreases it.
+			if firstTry {
+				t.waitingStreams++
+			}
+			ch = t.streamsQuotaAvailable
+			return false
+		}
+		if !firstTry {
+			t.waitingStreams--
+		}
+		t.streamQuota--
+		h := it.(*headerFrame)
+		h.streamID = t.nextID
+		t.nextID += 2
+		s.id = h.streamID
+		s.fc = &inFlow{limit: uint32(t.initialWindowSize)}
+		if t.streamQuota > 0 && t.waitingStreams > 0 {
+			select {
+			case t.streamsQuotaAvailable <- struct{}{}:
+			default:
+			}
+		}
+		return true
+	}
+	for {
+		success, err := t.controlBuf.executeAndPut(checkForStreamQuota, hdr)
+		if err != nil {
+			return nil, err
+		}
+		if success {
+			break
+		}
+		firstTry = false
+		select {
+		case <-ch:
+		case <-s.ctx.Done():
+			return nil, ContextErr(s.ctx.Err())
+		case <-t.goAway:
+			return nil, errStreamDrain
+		case <-t.ctx.Done():
+			return nil, ErrConnClosing
+		}
+	}
 	if t.statsHandler != nil {
 		outHeader := &stats.OutHeader{
 			Client:      true,
@@ -525,86 +625,97 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 // CloseStream clears the footprint of a stream when the stream is not needed any more.
 // This must not be executed in reader's goroutine.
 func (t *http2Client) CloseStream(s *Stream, err error) {
-	t.mu.Lock()
-	if t.activeStreams == nil {
-		t.mu.Unlock()
-		return
-	}
+	var (
+		rst     bool
+		rstCode http2.ErrCode
+	)
 	if err != nil {
-		// notify in-flight streams, before the deletion
-		s.write(recvMsg{err: err})
+		rst = true
+		rstCode = http2.ErrCodeCancel
 	}
-	delete(t.activeStreams, s.id)
-	if t.state == draining && len(t.activeStreams) == 0 {
-		// The transport is draining and s is the last live stream on t.
-		t.mu.Unlock()
-		t.Close()
+	t.closeStream(s, err, rst, rstCode, nil, nil, false)
+}
+
+func (t *http2Client) closeStream(s *Stream, err error, rst bool, rstCode http2.ErrCode, st *status.Status, mdata map[string][]string, eosReceived bool) {
+	// Set stream status to done.
+	if s.swapState(streamDone) == streamDone {
+		// If it was already done, return.
 		return
 	}
-	t.mu.Unlock()
-	// rstStream is true in case the stream is being closed at the client-side
-	// and the server needs to be intimated about it by sending a RST_STREAM
-	// frame.
-	// To make sure this frame is written to the wire before the headers of the
-	// next stream waiting for streamsQuota, we add to streamsQuota pool only
-	// after having acquired the writableChan to send RST_STREAM out (look at
-	// the controller() routine).
-	var rstStream bool
-	var rstError http2.ErrCode
-	defer func() {
-		// In case, the client doesn't have to send RST_STREAM to server
-		// we can safely add back to streamsQuota pool now.
-		if !rstStream {
-			t.streamsQuota.add(1)
-			return
-		}
-		t.controlBuf.put(&resetStream{s.id, rstError})
-	}()
-	s.mu.Lock()
-	rstStream = s.rstStream
-	rstError = s.rstError
-	if s.state == streamDone {
-		s.mu.Unlock()
-		return
+	// status and trailers can be updated here without any synchronization because the stream goroutine will
+	// only read it after it sees an io.EOF error from read or write and we'll write those errors
+	// only after updating this.
+	s.status = st
+	if len(mdata) > 0 {
+		s.trailer = mdata
 	}
-	if !s.headerDone {
+	if err != nil {
+		// This will unblock reads eventually.
+		s.write(recvMsg{err: err})
+	}
+	// This will unblock write.
+	close(s.done)
+	// If headerChan isn't closed, then close it.
+	if atomic.SwapUint32(&s.headerDone, 1) == 0 {
 		close(s.headerChan)
-		s.headerDone = true
 	}
-	s.state = streamDone
-	s.mu.Unlock()
-	if _, ok := err.(StreamError); ok {
-		rstStream = true
-		rstError = http2.ErrCodeCancel
+	cleanup := &cleanupStream{
+		streamID: s.id,
+		onWrite: func() {
+			t.mu.Lock()
+			if t.activeStreams != nil {
+				delete(t.activeStreams, s.id)
+			}
+			t.mu.Unlock()
+			if channelz.IsOn() {
+				t.czmu.Lock()
+				if eosReceived {
+					t.streamsSucceeded++
+				} else {
+					t.streamsFailed++
+				}
+				t.czmu.Unlock()
+			}
+		},
+		rst:     rst,
+		rstCode: rstCode,
+	}
+	addBackStreamQuota := func(interface{}) bool {
+		t.streamQuota++
+		if t.streamQuota > 0 && t.waitingStreams > 0 {
+			select {
+			case t.streamsQuotaAvailable <- struct{}{}:
+			default:
+			}
+		}
+		return true
 	}
+	t.controlBuf.executeAndPut(addBackStreamQuota, cleanup)
 }
 
 // Close kicks off the shutdown process of the transport. This should be called
 // only once on a transport. Once it is called, the transport should not be
 // accessed any more.
-func (t *http2Client) Close() (err error) {
+func (t *http2Client) Close() error {
 	t.mu.Lock()
+	// Make sure we only Close once.
 	if t.state == closing {
 		t.mu.Unlock()
-		return
+		return nil
 	}
 	t.state = closing
-	t.mu.Unlock()
-	t.cancel()
-	err = t.conn.Close()
-	t.mu.Lock()
 	streams := t.activeStreams
 	t.activeStreams = nil
 	t.mu.Unlock()
+	t.controlBuf.finish()
+	t.cancel()
+	err := t.conn.Close()
+	if channelz.IsOn() {
+		channelz.RemoveEntry(t.channelzID)
+	}
 	// Notify all active streams.
 	for _, s := range streams {
-		s.mu.Lock()
-		if !s.headerDone {
-			close(s.headerChan)
-			s.headerDone = true
-		}
-		s.mu.Unlock()
-		s.write(recvMsg{err: ErrConnClosing})
+		t.closeStream(s, ErrConnClosing, false, http2.ErrCodeNo, nil, nil, false)
 	}
 	if t.statsHandler != nil {
 		connEnd := &stats.ConnEnd{
@@ -622,8 +733,8 @@ func (t *http2Client) Close() (err error) {
 // closing.
 func (t *http2Client) GracefulClose() error {
 	t.mu.Lock()
-	switch t.state {
-	case closing, draining:
+	// Make sure we move to draining only from active.
+	if t.state == draining || t.state == closing {
 		t.mu.Unlock()
 		return nil
 	}
@@ -633,108 +744,41 @@ func (t *http2Client) GracefulClose() error {
 	if active == 0 {
 		return t.Close()
 	}
+	t.controlBuf.put(&incomingGoAway{})
 	return nil
 }
 
 // Write formats the data into HTTP2 data frame(s) and sends it out. The caller
 // should proceed only if Write returns nil.
 func (t *http2Client) Write(s *Stream, hdr []byte, data []byte, opts *Options) error {
-	select {
-	case <-s.ctx.Done():
-		return ContextErr(s.ctx.Err())
-	case <-t.ctx.Done():
-		return ErrConnClosing
-	default:
-	}
-
-	if hdr == nil && data == nil && opts.Last {
-		// stream.CloseSend uses this to send an empty frame with endStream=True
-		t.controlBuf.put(&dataFrame{streamID: s.id, endStream: true, f: func() {}})
-		return nil
-	}
-	// Add data to header frame so that we can equally distribute data across frames.
-	emptyLen := http2MaxFrameLen - len(hdr)
-	if emptyLen > len(data) {
-		emptyLen = len(data)
-	}
-	hdr = append(hdr, data[:emptyLen]...)
-	data = data[emptyLen:]
-	for idx, r := range [][]byte{hdr, data} {
-		for len(r) > 0 {
-			size := http2MaxFrameLen
-			// Wait until the stream has some quota to send the data.
-			quotaChan, quotaVer := s.sendQuotaPool.acquireWithVersion()
-			sq, err := wait(s.ctx, t.ctx, s.done, s.goAway, quotaChan)
-			if err != nil {
-				return err
-			}
-			// Wait until the transport has some quota to send the data.
-			tq, err := wait(s.ctx, t.ctx, s.done, s.goAway, t.sendQuotaPool.acquire())
-			if err != nil {
-				return err
-			}
-			if sq < size {
-				size = sq
-			}
-			if tq < size {
-				size = tq
-			}
-			if size > len(r) {
-				size = len(r)
-			}
-			p := r[:size]
-			ps := len(p)
-			if ps < tq {
-				// Overbooked transport quota. Return it back.
-				t.sendQuotaPool.add(tq - ps)
-			}
-			// Acquire local send quota to be able to write to the controlBuf.
-			ltq, err := wait(s.ctx, t.ctx, s.done, s.goAway, s.localSendQuota.acquire())
-			if err != nil {
-				if _, ok := err.(ConnectionError); !ok {
-					t.sendQuotaPool.add(ps)
-				}
-				return err
-			}
-			s.localSendQuota.add(ltq - ps) // It's ok if we make it negative.
-			var endStream bool
-			// See if this is the last frame to be written.
-			if opts.Last {
-				if len(r)-size == 0 { // No more data in r after this iteration.
-					if idx == 0 { // We're writing data header.
-						if len(data) == 0 { // There's no data to follow.
-							endStream = true
-						}
-					} else { // We're writing data.
-						endStream = true
-					}
-				}
-			}
-			success := func() {
-				t.controlBuf.put(&dataFrame{streamID: s.id, endStream: endStream, d: p, f: func() { s.localSendQuota.add(ps) }})
-				if ps < sq {
-					s.sendQuotaPool.lockedAdd(sq - ps)
-				}
-				r = r[ps:]
-			}
-			failure := func() {
-				s.sendQuotaPool.lockedAdd(sq)
-			}
-			if !s.sendQuotaPool.compareAndExecute(quotaVer, success, failure) {
-				t.sendQuotaPool.add(ps)
-				s.localSendQuota.add(ps)
-			}
+	if opts.Last {
+		// If it's the last message, update stream state.
+		if !s.compareAndSwapState(streamActive, streamWriteDone) {
+			return errStreamDone
 		}
+	} else if s.getState() != streamActive {
+		return errStreamDone
 	}
-	if !opts.Last {
-		return nil
-	}
-	s.mu.Lock()
-	if s.state != streamDone {
-		s.state = streamWriteDone
+	df := &dataFrame{
+		streamID:  s.id,
+		endStream: opts.Last,
+	}
+	if hdr != nil || data != nil { // If it's not an empty data frame.
+		// Add some data to grpc message header so that we can equally
+		// distribute bytes across frames.
+		emptyLen := http2MaxFrameLen - len(hdr)
+		if emptyLen > len(data) {
+			emptyLen = len(data)
+		}
+		hdr = append(hdr, data[:emptyLen]...)
+		data = data[emptyLen:]
+		df.h, df.d = hdr, data
+		// TODO(mmukhi): The above logic in this if can be moved to loopyWriter's data handler.
+		if err := s.wq.get(int32(len(hdr) + len(data))); err != nil {
+			return err
+		}
 	}
-	s.mu.Unlock()
-	return nil
+	return t.controlBuf.put(df)
 }
 
 func (t *http2Client) getStream(f http2.Frame) (*Stream, bool) {
@@ -748,34 +792,17 @@ func (t *http2Client) getStream(f http2.Frame) (*Stream, bool) {
 // of stream if the application is requesting data larger in size than
 // the window.
 func (t *http2Client) adjustWindow(s *Stream, n uint32) {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	if s.state == streamDone {
-		return
-	}
 	if w := s.fc.maybeAdjust(n); w > 0 {
-		// Piggyback connection's window update along.
-		if cw := t.fc.resetPendingUpdate(); cw > 0 {
-			t.controlBuf.put(&windowUpdate{0, cw})
-		}
-		t.controlBuf.put(&windowUpdate{s.id, w})
+		t.controlBuf.put(&outgoingWindowUpdate{streamID: s.id, increment: w})
 	}
 }
 
-// updateWindow adjusts the inbound quota for the stream and the transport.
-// Window updates will deliver to the controller for sending when
-// the cumulative quota exceeds the corresponding threshold.
+// updateWindow adjusts the inbound quota for the stream.
+// Window updates will be sent out when the cumulative quota
+// exceeds the corresponding threshold.
 func (t *http2Client) updateWindow(s *Stream, n uint32) {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	if s.state == streamDone {
-		return
-	}
 	if w := s.fc.onRead(n); w > 0 {
-		if cw := t.fc.resetPendingUpdate(); cw > 0 {
-			t.controlBuf.put(&windowUpdate{0, cw})
-		}
-		t.controlBuf.put(&windowUpdate{s.id, w})
+		t.controlBuf.put(&outgoingWindowUpdate{streamID: s.id, increment: w})
 	}
 }
 
@@ -787,15 +814,17 @@ func (t *http2Client) updateFlowControl(n uint32) {
 	for _, s := range t.activeStreams {
 		s.fc.newLimit(n)
 	}
-	t.initialWindowSize = int32(n)
 	t.mu.Unlock()
-	t.controlBuf.put(&windowUpdate{0, t.fc.newLimit(n)})
-	t.controlBuf.put(&settings{
-		ack: false,
+	updateIWS := func(interface{}) bool {
+		t.initialWindowSize = int32(n)
+		return true
+	}
+	t.controlBuf.executeAndPut(updateIWS, &outgoingWindowUpdate{streamID: 0, increment: t.fc.newLimit(n)})
+	t.controlBuf.put(&outgoingSettings{
 		ss: []http2.Setting{
 			{
 				ID:  http2.SettingInitialWindowSize,
-				Val: uint32(n),
+				Val: n,
 			},
 		},
 	})
@@ -805,7 +834,7 @@ func (t *http2Client) handleData(f *http2.DataFrame) {
 	size := f.Header().Length
 	var sendBDPPing bool
 	if t.bdpEst != nil {
-		sendBDPPing = t.bdpEst.add(uint32(size))
+		sendBDPPing = t.bdpEst.add(size)
 	}
 	// Decouple connection's flow control from application's read.
 	// An update on connection's flow control should not depend on
@@ -816,21 +845,24 @@ func (t *http2Client) handleData(f *http2.DataFrame) {
 	// active(fast) streams from starving in presence of slow or
 	// inactive streams.
 	//
-	// Furthermore, if a bdpPing is being sent out we can piggyback
-	// connection's window update for the bytes we just received.
+	if w := t.fc.onData(size); w > 0 {
+		t.controlBuf.put(&outgoingWindowUpdate{
+			streamID:  0,
+			increment: w,
+		})
+	}
 	if sendBDPPing {
-		if size != 0 { // Could've been an empty data frame.
-			t.controlBuf.put(&windowUpdate{0, uint32(size)})
+		// Avoid excessive ping detection (e.g. in an L7 proxy)
+		// by sending a window update prior to the BDP ping.
+
+		if w := t.fc.reset(); w > 0 {
+			t.controlBuf.put(&outgoingWindowUpdate{
+				streamID:  0,
+				increment: w,
+			})
 		}
+
 		t.controlBuf.put(bdpPing)
-	} else {
-		if err := t.fc.onData(uint32(size)); err != nil {
-			t.Close()
-			return
-		}
-		if w := t.fc.onRead(uint32(size)); w > 0 {
-			t.controlBuf.put(&windowUpdate{0, w})
-		}
 	}
 	// Select the right stream to dispatch.
 	s, ok := t.getStream(f)
@@ -838,25 +870,15 @@ func (t *http2Client) handleData(f *http2.DataFrame) {
 		return
 	}
 	if size > 0 {
-		s.mu.Lock()
-		if s.state == streamDone {
-			s.mu.Unlock()
-			return
-		}
-		if err := s.fc.onData(uint32(size)); err != nil {
-			s.rstStream = true
-			s.rstError = http2.ErrCodeFlowControl
-			s.finish(status.New(codes.Internal, err.Error()))
-			s.mu.Unlock()
-			s.write(recvMsg{err: io.EOF})
+		if err := s.fc.onData(size); err != nil {
+			t.closeStream(s, io.EOF, true, http2.ErrCodeFlowControl, status.New(codes.Internal, err.Error()), nil, false)
 			return
 		}
 		if f.Header().Flags.Has(http2.FlagDataPadded) {
-			if w := s.fc.onRead(uint32(size) - uint32(len(f.Data()))); w > 0 {
-				t.controlBuf.put(&windowUpdate{s.id, w})
+			if w := s.fc.onRead(size - uint32(len(f.Data()))); w > 0 {
+				t.controlBuf.put(&outgoingWindowUpdate{s.id, w})
 			}
 		}
-		s.mu.Unlock()
 		// TODO(bradfitz, zhaoq): A copy is required here because there is no
 		// guarantee f.Data() is consumed before the arrival of next frame.
 		// Can this copy be eliminated?
@@ -869,14 +891,7 @@ func (t *http2Client) handleData(f *http2.DataFrame) {
 	// The server has closed the stream without sending trailers.  Record that
 	// the read direction is closed, and set the status appropriately.
 	if f.FrameHeader.Flags.Has(http2.FlagDataEndStream) {
-		s.mu.Lock()
-		if s.state == streamDone {
-			s.mu.Unlock()
-			return
-		}
-		s.finish(status.New(codes.Internal, "server closed the stream without sending trailers"))
-		s.mu.Unlock()
-		s.write(recvMsg{err: io.EOF})
+		t.closeStream(s, io.EOF, false, http2.ErrCodeNo, status.New(codes.Internal, "server closed the stream without sending trailers"), nil, true)
 	}
 }
 
@@ -885,36 +900,55 @@ func (t *http2Client) handleRSTStream(f *http2.RSTStreamFrame) {
 	if !ok {
 		return
 	}
-	s.mu.Lock()
-	if s.state == streamDone {
-		s.mu.Unlock()
-		return
-	}
-	if !s.headerDone {
-		close(s.headerChan)
-		s.headerDone = true
+	if f.ErrCode == http2.ErrCodeRefusedStream {
+		// The stream was unprocessed by the server.
+		atomic.StoreUint32(&s.unprocessed, 1)
 	}
-	statusCode, ok := http2ErrConvTab[http2.ErrCode(f.ErrCode)]
+	statusCode, ok := http2ErrConvTab[f.ErrCode]
 	if !ok {
 		warningf("transport: http2Client.handleRSTStream found no mapped gRPC status for the received http2 error %v", f.ErrCode)
 		statusCode = codes.Unknown
 	}
-	s.finish(status.Newf(statusCode, "stream terminated by RST_STREAM with error code: %v", f.ErrCode))
-	s.mu.Unlock()
-	s.write(recvMsg{err: io.EOF})
+	t.closeStream(s, io.EOF, false, http2.ErrCodeNo, status.Newf(statusCode, "stream terminated by RST_STREAM with error code: %v", f.ErrCode), nil, false)
 }
 
-func (t *http2Client) handleSettings(f *http2.SettingsFrame) {
+func (t *http2Client) handleSettings(f *http2.SettingsFrame, isFirst bool) {
 	if f.IsAck() {
 		return
 	}
+	var maxStreams *uint32
 	var ss []http2.Setting
 	f.ForeachSetting(func(s http2.Setting) error {
+		if s.ID == http2.SettingMaxConcurrentStreams {
+			maxStreams = new(uint32)
+			*maxStreams = s.Val
+			return nil
+		}
 		ss = append(ss, s)
 		return nil
 	})
-	// The settings will be applied once the ack is sent.
-	t.controlBuf.put(&settings{ack: true, ss: ss})
+	if isFirst && maxStreams == nil {
+		maxStreams = new(uint32)
+		*maxStreams = math.MaxUint32
+	}
+	sf := &incomingSettings{
+		ss: ss,
+	}
+	if maxStreams == nil {
+		t.controlBuf.put(sf)
+		return
+	}
+	updateStreamQuota := func(interface{}) bool {
+		delta := int64(*maxStreams) - int64(t.maxConcurrentStreams)
+		t.maxConcurrentStreams = *maxStreams
+		t.streamQuota += delta
+		if delta > 0 && t.waitingStreams > 0 {
+			close(t.streamsQuotaAvailable) // wake all of them up.
+			t.streamsQuotaAvailable = make(chan struct{}, 1)
+		}
+		return true
+	}
+	t.controlBuf.executeAndPut(updateStreamQuota, sf)
 }
 
 func (t *http2Client) handlePing(f *http2.PingFrame) {
@@ -932,7 +966,7 @@ func (t *http2Client) handlePing(f *http2.PingFrame) {
 
 func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
 	t.mu.Lock()
-	if t.state != reachable && t.state != draining {
+	if t.state == closing {
 		t.mu.Unlock()
 		return
 	}
@@ -945,12 +979,16 @@ func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
 		t.Close()
 		return
 	}
-	// A client can receive multiple GoAways from server (look at https://github.com/grpc/grpc-go/issues/1387).
-	// The idea is that the first GoAway will be sent with an ID of MaxInt32 and the second GoAway will be sent after an RTT delay
-	// with the ID of the last stream the server will process.
-	// Therefore, when we get the first GoAway we don't really close any streams. While in case of second GoAway we
-	// close all streams created after the second GoAwayId. This way streams that were in-flight while the GoAway from server
-	// was being sent don't get killed.
+	// A client can receive multiple GoAways from the server (see
+	// https://github.com/grpc/grpc-go/issues/1387).  The idea is that the first
+	// GoAway will be sent with an ID of MaxInt32 and the second GoAway will be
+	// sent after an RTT delay with the ID of the last stream the server will
+	// process.
+	//
+	// Therefore, when we get the first GoAway we don't necessarily close any
+	// streams. While in case of second GoAway we close all streams created after
+	// the GoAwayId. This way streams that were in-flight while the GoAway from
+	// server was being sent don't get killed.
 	select {
 	case <-t.goAway: // t.goAway has been closed (i.e.,multiple GoAways).
 		// If there are multiple GoAways the first one should always have an ID greater than the following ones.
@@ -963,6 +1001,7 @@ func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
 		t.setGoAwayReason(f)
 		close(t.goAway)
 		t.state = draining
+		t.controlBuf.put(&incomingGoAway{})
 	}
 	// All streams with IDs greater than the GoAwayId
 	// and smaller than the previous GoAway ID should be killed.
@@ -972,7 +1011,9 @@ func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
 	}
 	for streamID, stream := range t.activeStreams {
 		if streamID > id && streamID <= upperLimit {
-			close(stream.goAway)
+			// The stream was unprocessed by the server.
+			atomic.StoreUint32(&stream.unprocessed, 1)
+			t.closeStream(stream, errStreamDrain, false, http2.ErrCodeNo, statusGoAway, nil, false)
 		}
 	}
 	t.prevGoAwayID = id
@@ -988,11 +1029,11 @@ func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
 // It expects a lock on transport's mutext to be held by
 // the caller.
 func (t *http2Client) setGoAwayReason(f *http2.GoAwayFrame) {
-	t.goAwayReason = NoReason
+	t.goAwayReason = GoAwayNoReason
 	switch f.ErrCode {
 	case http2.ErrCodeEnhanceYourCalm:
 		if string(f.DebugData()) == "too_many_pings" {
-			t.goAwayReason = TooManyPings
+			t.goAwayReason = GoAwayTooManyPings
 		}
 	}
 }
@@ -1004,15 +1045,10 @@ func (t *http2Client) GetGoAwayReason() GoAwayReason {
 }
 
 func (t *http2Client) handleWindowUpdate(f *http2.WindowUpdateFrame) {
-	id := f.Header().StreamID
-	incr := f.Increment
-	if id == 0 {
-		t.sendQuotaPool.add(int(incr))
-		return
-	}
-	if s, ok := t.getStream(f); ok {
-		s.sendQuotaPool.add(int(incr))
-	}
+	t.controlBuf.put(&incomingWindowUpdate{
+		streamID:  f.Header().StreamID,
+		increment: f.Increment,
+	})
 }
 
 // operateHeaders takes action on the decoded headers.
@@ -1021,18 +1057,10 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 	if !ok {
 		return
 	}
-	s.mu.Lock()
-	s.bytesReceived = true
-	s.mu.Unlock()
+	atomic.StoreUint32(&s.bytesReceived, 1)
 	var state decodeState
 	if err := state.decodeResponseHeader(frame); err != nil {
-		s.mu.Lock()
-		if !s.headerDone {
-			close(s.headerChan)
-			s.headerDone = true
-		}
-		s.mu.Unlock()
-		s.write(recvMsg{err: err})
+		t.closeStream(s, err, true, http2.ErrCodeProtocol, nil, nil, false)
 		// Something wrong. Stops reading even when there is remaining.
 		return
 	}
@@ -1056,40 +1084,25 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 			}
 		}
 	}()
-
-	s.mu.Lock()
-	if !endStream {
-		s.recvCompress = state.encoding
-	}
-	if !s.headerDone {
-		if !endStream && len(state.mdata) > 0 {
-			s.header = state.mdata
+	// If headers haven't been received yet.
+	if atomic.SwapUint32(&s.headerDone, 1) == 0 {
+		if !endStream {
+			// Headers frame is not actually a trailers-only frame.
+			isHeader = true
+			// These values can be set without any synchronization because
+			// stream goroutine will read it only after seeing a closed
+			// headerChan which we'll close after setting this.
+			s.recvCompress = state.encoding
+			if len(state.mdata) > 0 {
+				s.header = state.mdata
+			}
 		}
 		close(s.headerChan)
-		s.headerDone = true
-		isHeader = true
 	}
-	if !endStream || s.state == streamDone {
-		s.mu.Unlock()
+	if !endStream {
 		return
 	}
-
-	if len(state.mdata) > 0 {
-		s.trailer = state.mdata
-	}
-	s.finish(state.status())
-	s.mu.Unlock()
-	s.write(recvMsg{err: io.EOF})
-}
-
-func handleMalformedHTTP2(s *Stream, err error) {
-	s.mu.Lock()
-	if !s.headerDone {
-		close(s.headerChan)
-		s.headerDone = true
-	}
-	s.mu.Unlock()
-	s.write(recvMsg{err: err})
+	t.closeStream(s, io.EOF, false, http2.ErrCodeNo, state.status(), state.mdata, true)
 }
 
 // reader runs as a separate goroutine in charge of reading data from network
@@ -1099,24 +1112,30 @@ func handleMalformedHTTP2(s *Stream, err error) {
 // optimal.
 // TODO(zhaoq): Check the validity of the incoming frame sequence.
 func (t *http2Client) reader() {
+	defer close(t.readerDone)
 	// Check the validity of server preface.
 	frame, err := t.framer.fr.ReadFrame()
 	if err != nil {
 		t.Close()
 		return
 	}
-	atomic.CompareAndSwapUint32(&t.activity, 0, 1)
+	if t.keepaliveEnabled {
+		atomic.CompareAndSwapUint32(&t.activity, 0, 1)
+	}
 	sf, ok := frame.(*http2.SettingsFrame)
 	if !ok {
 		t.Close()
 		return
 	}
-	t.handleSettings(sf)
+	t.onSuccess()
+	t.handleSettings(sf, true)
 
 	// loop to keep reading incoming messages on this transport.
 	for {
 		frame, err := t.framer.fr.ReadFrame()
-		atomic.CompareAndSwapUint32(&t.activity, 0, 1)
+		if t.keepaliveEnabled {
+			atomic.CompareAndSwapUint32(&t.activity, 0, 1)
+		}
 		if err != nil {
 			// Abort an active stream if the http2.Framer returns a
 			// http2.StreamError. This can happen only if the server's response
@@ -1127,7 +1146,7 @@ func (t *http2Client) reader() {
 				t.mu.Unlock()
 				if s != nil {
 					// use error detail to provide better err message
-					handleMalformedHTTP2(s, streamErrorf(http2ErrConvTab[se.Code], "%v", t.framer.fr.ErrorDetail()))
+					t.closeStream(s, streamErrorf(http2ErrConvTab[se.Code], "%v", t.framer.fr.ErrorDetail()), true, http2.ErrCodeProtocol, nil, nil, false)
 				}
 				continue
 			} else {
@@ -1144,7 +1163,7 @@ func (t *http2Client) reader() {
 		case *http2.RSTStreamFrame:
 			t.handleRSTStream(frame)
 		case *http2.SettingsFrame:
-			t.handleSettings(frame)
+			t.handleSettings(frame, false)
 		case *http2.PingFrame:
 			t.handlePing(frame)
 		case *http2.GoAwayFrame:
@@ -1157,107 +1176,6 @@ func (t *http2Client) reader() {
 	}
 }
 
-func (t *http2Client) applySettings(ss []http2.Setting) {
-	for _, s := range ss {
-		switch s.ID {
-		case http2.SettingMaxConcurrentStreams:
-			// TODO(zhaoq): This is a hack to avoid significant refactoring of the
-			// code to deal with the unrealistic int32 overflow. Probably will try
-			// to find a better way to handle this later.
-			if s.Val > math.MaxInt32 {
-				s.Val = math.MaxInt32
-			}
-			t.mu.Lock()
-			ms := t.maxStreams
-			t.maxStreams = int(s.Val)
-			t.mu.Unlock()
-			t.streamsQuota.add(int(s.Val) - ms)
-		case http2.SettingInitialWindowSize:
-			t.mu.Lock()
-			for _, stream := range t.activeStreams {
-				// Adjust the sending quota for each stream.
-				stream.sendQuotaPool.addAndUpdate(int(s.Val) - int(t.streamSendQuota))
-			}
-			t.streamSendQuota = s.Val
-			t.mu.Unlock()
-		}
-	}
-}
-
-// TODO(mmukhi): A lot of this code(and code in other places in the tranpsort layer)
-// is duplicated between the client and the server.
-// The transport layer needs to be refactored to take care of this.
-func (t *http2Client) itemHandler(i item) error {
-	var err error
-	switch i := i.(type) {
-	case *dataFrame:
-		err = t.framer.fr.WriteData(i.streamID, i.endStream, i.d)
-		if err == nil {
-			i.f()
-		}
-	case *headerFrame:
-		t.hBuf.Reset()
-		for _, f := range i.hf {
-			t.hEnc.WriteField(f)
-		}
-		endHeaders := false
-		first := true
-		for !endHeaders {
-			size := t.hBuf.Len()
-			if size > http2MaxFrameLen {
-				size = http2MaxFrameLen
-			} else {
-				endHeaders = true
-			}
-			if first {
-				first = false
-				err = t.framer.fr.WriteHeaders(http2.HeadersFrameParam{
-					StreamID:      i.streamID,
-					BlockFragment: t.hBuf.Next(size),
-					EndStream:     i.endStream,
-					EndHeaders:    endHeaders,
-				})
-			} else {
-				err = t.framer.fr.WriteContinuation(
-					i.streamID,
-					endHeaders,
-					t.hBuf.Next(size),
-				)
-			}
-			if err != nil {
-				return err
-			}
-		}
-	case *windowUpdate:
-		err = t.framer.fr.WriteWindowUpdate(i.streamID, i.increment)
-	case *settings:
-		if i.ack {
-			t.applySettings(i.ss)
-			err = t.framer.fr.WriteSettingsAck()
-		} else {
-			err = t.framer.fr.WriteSettings(i.ss...)
-		}
-	case *resetStream:
-		// If the server needs to be to intimated about stream closing,
-		// then we need to make sure the RST_STREAM frame is written to
-		// the wire before the headers of the next stream waiting on
-		// streamQuota. We ensure this by adding to the streamsQuota pool
-		// only after having acquired the writableChan to send RST_STREAM.
-		err = t.framer.fr.WriteRSTStream(i.streamID, i.code)
-		t.streamsQuota.add(1)
-	case *flushIO:
-		err = t.framer.writer.Flush()
-	case *ping:
-		if !i.ack {
-			t.bdpEst.timesnap(i.data)
-		}
-		err = t.framer.fr.WritePing(i.ack, i.data)
-	default:
-		errorf("transport: http2Client.controller got unexpected item type %v", i)
-	}
-	return err
-}
-
 // keepalive running in a separate goroutune makes sure the connection is alive by sending pings.
 func (t *http2Client) keepalive() {
 	p := &ping{data: [8]byte{}}
@@ -1284,6 +1202,11 @@ func (t *http2Client) keepalive() {
 				}
 			} else {
 				t.mu.Unlock()
+				if channelz.IsOn() {
+					t.czmu.Lock()
+					t.kpCount++
+					t.czmu.Unlock()
+				}
 				// Send ping.
 				t.controlBuf.put(p)
 			}
@@ -1320,3 +1243,56 @@ func (t *http2Client) Error() <-chan struct{} {
 func (t *http2Client) GoAway() <-chan struct{} {
 	return t.goAway
 }
+
+func (t *http2Client) ChannelzMetric() *channelz.SocketInternalMetric {
+	t.czmu.RLock()
+	s := channelz.SocketInternalMetric{
+		StreamsStarted:                  t.streamsStarted,
+		StreamsSucceeded:                t.streamsSucceeded,
+		StreamsFailed:                   t.streamsFailed,
+		MessagesSent:                    t.msgSent,
+		MessagesReceived:                t.msgRecv,
+		KeepAlivesSent:                  t.kpCount,
+		LastLocalStreamCreatedTimestamp: t.lastStreamCreated,
+		LastMessageSentTimestamp:        t.lastMsgSent,
+		LastMessageReceivedTimestamp:    t.lastMsgRecv,
+		LocalFlowControlWindow:          int64(t.fc.getSize()),
+		//socket options
+		LocalAddr:  t.localAddr,
+		RemoteAddr: t.remoteAddr,
+		// Security
+		// RemoteName :
+	}
+	t.czmu.RUnlock()
+	s.RemoteFlowControlWindow = t.getOutFlowWindow()
+	return &s
+}
+
+func (t *http2Client) IncrMsgSent() {
+	t.czmu.Lock()
+	t.msgSent++
+	t.lastMsgSent = time.Now()
+	t.czmu.Unlock()
+}
+
+func (t *http2Client) IncrMsgRecv() {
+	t.czmu.Lock()
+	t.msgRecv++
+	t.lastMsgRecv = time.Now()
+	t.czmu.Unlock()
+}
+
+func (t *http2Client) getOutFlowWindow() int64 {
+	resp := make(chan uint32, 1)
+	timer := time.NewTimer(time.Second)
+	defer timer.Stop()
+	t.controlBuf.put(&outFlowControlSizeRequest{resp})
+	select {
+	case sz := <-resp:
+		return int64(sz)
+	case <-t.ctxDone:
+		return -1
+	case <-timer.C:
+		return -2
+	}
+}
diff --git a/vendor/google.golang.org/grpc/transport/http2_server.go b/vendor/google.golang.org/grpc/transport/http2_server.go
index bad29b8..19acedb 100644
--- a/vendor/google.golang.org/grpc/transport/http2_server.go
+++ b/vendor/google.golang.org/grpc/transport/http2_server.go
@@ -24,7 +24,6 @@ import (
 	"fmt"
 	"io"
 	"math"
-	"math/rand"
 	"net"
 	"strconv"
 	"sync"
@@ -35,8 +34,12 @@ import (
 	"golang.org/x/net/context"
 	"golang.org/x/net/http2"
 	"golang.org/x/net/http2/hpack"
+
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/internal/channelz"
+	"google.golang.org/grpc/internal/grpcrand"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/peer"
@@ -52,25 +55,25 @@ var ErrIllegalHeaderWrite = errors.New("transport: the stream is done or WriteHe
 // http2Server implements the ServerTransport interface with HTTP2.
 type http2Server struct {
 	ctx         context.Context
+	ctxDone     <-chan struct{} // Cache the context.Done() chan
 	cancel      context.CancelFunc
 	conn        net.Conn
+	loopy       *loopyWriter
+	readerDone  chan struct{} // sync point to enable testing.
+	writerDone  chan struct{} // sync point to enable testing.
 	remoteAddr  net.Addr
 	localAddr   net.Addr
 	maxStreamID uint32               // max stream ID ever seen
 	authInfo    credentials.AuthInfo // auth info about the connection
 	inTapHandle tap.ServerInHandle
 	framer      *framer
-	hBuf        *bytes.Buffer  // the buffer for HPACK encoding
-	hEnc        *hpack.Encoder // HPACK encoder
 	// The max number of concurrent streams.
 	maxStreams uint32
 	// controlBuf delivers all the control related tasks (e.g., window
 	// updates, reset streams, and various settings) to the controller.
 	controlBuf *controlBuffer
-	fc         *inFlow
-	// sendQuotaPool provides flow control to outbound message.
-	sendQuotaPool *quotaPool
-	stats         stats.Handler
+	fc         *trInFlow
+	stats      stats.Handler
 	// Flag to keep track of reading activity on transport.
 	// 1 is true and 0 is false.
 	activity uint32 // Accessed atomically.
@@ -101,13 +104,27 @@ type http2Server struct {
 	drainChan     chan struct{}
 	state         transportState
 	activeStreams map[uint32]*Stream
-	// the per-stream outbound flow control window size set by the peer.
-	streamSendQuota uint32
 	// idle is the time instant when the connection went idle.
 	// This is either the beginning of the connection or when the number of
 	// RPCs go down to 0.
 	// When the connection is busy, this value is set to 0.
 	idle time.Time
+
+	// Fields below are for channelz metric collection.
+	channelzID int64 // channelz unique identification number
+	czmu       sync.RWMutex
+	kpCount    int64
+	// The number of streams that have started, including already finished ones.
+	streamsStarted int64
+	// The number of streams that have ended successfully by sending frame with
+	// EoS bit set.
+	streamsSucceeded  int64
+	streamsFailed     int64
+	lastStreamCreated time.Time
+	msgSent           int64
+	msgRecv           int64
+	lastMsgSent       time.Time
+	lastMsgRecv       time.Time
 }
 
 // newHTTP2Server constructs a ServerTransport based on HTTP2. ConnectionError is
@@ -152,12 +169,12 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 			Val: uint32(iwz)})
 	}
 	if err := framer.fr.WriteSettings(isettings...); err != nil {
-		return nil, connectionErrorf(true, err, "transport: %v", err)
+		return nil, connectionErrorf(false, err, "transport: %v", err)
 	}
 	// Adjust the connection flow control window if needed.
 	if delta := uint32(icwz - defaultWindowSize); delta > 0 {
 		if err := framer.fr.WriteWindowUpdate(0, delta); err != nil {
-			return nil, connectionErrorf(true, err, "transport: %v", err)
+			return nil, connectionErrorf(false, err, "transport: %v", err)
 		}
 	}
 	kp := config.KeepaliveParams
@@ -182,32 +199,30 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 	if kep.MinTime == 0 {
 		kep.MinTime = defaultKeepalivePolicyMinTime
 	}
-	var buf bytes.Buffer
 	ctx, cancel := context.WithCancel(context.Background())
 	t := &http2Server{
 		ctx:               ctx,
 		cancel:            cancel,
+		ctxDone:           ctx.Done(),
 		conn:              conn,
 		remoteAddr:        conn.RemoteAddr(),
 		localAddr:         conn.LocalAddr(),
 		authInfo:          config.AuthInfo,
 		framer:            framer,
-		hBuf:              &buf,
-		hEnc:              hpack.NewEncoder(&buf),
+		readerDone:        make(chan struct{}),
+		writerDone:        make(chan struct{}),
 		maxStreams:        maxStreams,
 		inTapHandle:       config.InTapHandle,
-		controlBuf:        newControlBuffer(),
-		fc:                &inFlow{limit: uint32(icwz)},
-		sendQuotaPool:     newQuotaPool(defaultWindowSize),
+		fc:                &trInFlow{limit: uint32(icwz)},
 		state:             reachable,
 		activeStreams:     make(map[uint32]*Stream),
-		streamSendQuota:   defaultWindowSize,
 		stats:             config.StatsHandler,
 		kp:                kp,
 		idle:              time.Now(),
 		kep:               kep,
 		initialWindowSize: iwz,
 	}
+	t.controlBuf = newControlBuffer(t.ctxDone)
 	if dynamicWindow {
 		t.bdpEst = &bdpEstimator{
 			bdp:               initialWindowSize,
@@ -222,10 +237,48 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 		connBegin := &stats.ConnBegin{}
 		t.stats.HandleConn(t.ctx, connBegin)
 	}
+	if channelz.IsOn() {
+		t.channelzID = channelz.RegisterNormalSocket(t, config.ChannelzParentID, "")
+	}
 	t.framer.writer.Flush()
+
+	defer func() {
+		if err != nil {
+			t.Close()
+		}
+	}()
+
+	// Check the validity of client preface.
+	preface := make([]byte, len(clientPreface))
+	if _, err := io.ReadFull(t.conn, preface); err != nil {
+		return nil, connectionErrorf(false, err, "transport: http2Server.HandleStreams failed to receive the preface from client: %v", err)
+	}
+	if !bytes.Equal(preface, clientPreface) {
+		return nil, connectionErrorf(false, nil, "transport: http2Server.HandleStreams received bogus greeting from client: %q", preface)
+	}
+
+	frame, err := t.framer.fr.ReadFrame()
+	if err == io.EOF || err == io.ErrUnexpectedEOF {
+		return nil, err
+	}
+	if err != nil {
+		return nil, connectionErrorf(false, err, "transport: http2Server.HandleStreams failed to read initial settings frame: %v", err)
+	}
+	atomic.StoreUint32(&t.activity, 1)
+	sf, ok := frame.(*http2.SettingsFrame)
+	if !ok {
+		return nil, connectionErrorf(false, nil, "transport: http2Server.HandleStreams saw invalid preface type %T from client", frame)
+	}
+	t.handleSettings(sf)
+
 	go func() {
-		loopyWriter(t.ctx, t.controlBuf, t.itemHandler)
-		t.Close()
+		t.loopy = newLoopyWriter(serverSide, t.framer, t.controlBuf, t.bdpEst)
+		t.loopy.ssGoAwayHandler = t.outgoingGoAwayHandler
+		if err := t.loopy.run(); err != nil {
+			errorf("transport: loopyWriter.run returning. Err: %v", err)
+		}
+		t.conn.Close()
+		close(t.writerDone)
 	}()
 	go t.keepalive()
 	return t, nil
@@ -234,12 +287,16 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 // operateHeader takes action on the decoded headers.
 func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(*Stream), traceCtx func(context.Context, string) context.Context) (close bool) {
 	streamID := frame.Header().StreamID
-
 	var state decodeState
 	for _, hf := range frame.Fields {
 		if err := state.processHeaderField(hf); err != nil {
 			if se, ok := err.(StreamError); ok {
-				t.controlBuf.put(&resetStream{streamID, statusCodeConvTab[se.Code]})
+				t.controlBuf.put(&cleanupStream{
+					streamID: streamID,
+					rst:      true,
+					rstCode:  statusCodeConvTab[se.Code],
+					onWrite:  func() {},
+				})
 			}
 			return
 		}
@@ -247,14 +304,14 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 
 	buf := newRecvBuffer()
 	s := &Stream{
-		id:           streamID,
-		st:           t,
-		buf:          buf,
-		fc:           &inFlow{limit: uint32(t.initialWindowSize)},
-		recvCompress: state.encoding,
-		method:       state.method,
+		id:             streamID,
+		st:             t,
+		buf:            buf,
+		fc:             &inFlow{limit: uint32(t.initialWindowSize)},
+		recvCompress:   state.encoding,
+		method:         state.method,
+		contentSubtype: state.contentSubtype,
 	}
-
 	if frame.StreamEnded() {
 		// s is just created by the caller. No lock needed.
 		s.state = streamReadDone
@@ -272,10 +329,6 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 		pr.AuthInfo = t.authInfo
 	}
 	s.ctx = peer.NewContext(s.ctx, pr)
-	// Cache the current stream to the context so that the server application
-	// can find out. Required when the server wants to send some metadata
-	// back to the client (unary call only).
-	s.ctx = newContextWithStream(s.ctx, s)
 	// Attach the received metadata to the context.
 	if len(state.mdata) > 0 {
 		s.ctx = metadata.NewIncomingContext(s.ctx, state.mdata)
@@ -294,7 +347,12 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 		s.ctx, err = t.inTapHandle(s.ctx, info)
 		if err != nil {
 			warningf("transport: http2Server.operateHeaders got an error from InTapHandle: %v", err)
-			t.controlBuf.put(&resetStream{s.id, http2.ErrCodeRefusedStream})
+			t.controlBuf.put(&cleanupStream{
+				streamID: s.id,
+				rst:      true,
+				rstCode:  http2.ErrCodeRefusedStream,
+				onWrite:  func() {},
+			})
 			return
 		}
 	}
@@ -305,7 +363,12 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 	}
 	if uint32(len(t.activeStreams)) >= t.maxStreams {
 		t.mu.Unlock()
-		t.controlBuf.put(&resetStream{streamID, http2.ErrCodeRefusedStream})
+		t.controlBuf.put(&cleanupStream{
+			streamID: streamID,
+			rst:      true,
+			rstCode:  http2.ErrCodeRefusedStream,
+			onWrite:  func() {},
+		})
 		return
 	}
 	if streamID%2 != 1 || streamID <= t.maxStreamID {
@@ -315,13 +378,17 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 		return true
 	}
 	t.maxStreamID = streamID
-	s.sendQuotaPool = newQuotaPool(int(t.streamSendQuota))
-	s.localSendQuota = newQuotaPool(defaultLocalSendQuota)
 	t.activeStreams[streamID] = s
 	if len(t.activeStreams) == 1 {
 		t.idle = time.Time{}
 	}
 	t.mu.Unlock()
+	if channelz.IsOn() {
+		t.czmu.Lock()
+		t.streamsStarted++
+		t.lastStreamCreated = time.Now()
+		t.czmu.Unlock()
+	}
 	s.requestRead = func(n int) {
 		t.adjustWindow(s, uint32(n))
 	}
@@ -337,15 +404,23 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 		}
 		t.stats.HandleRPC(s.ctx, inHeader)
 	}
+	s.ctxDone = s.ctx.Done()
+	s.wq = newWriteQuota(defaultWriteQuota, s.ctxDone)
 	s.trReader = &transportReader{
 		reader: &recvBufferReader{
-			ctx:  s.ctx,
-			recv: s.buf,
+			ctx:     s.ctx,
+			ctxDone: s.ctxDone,
+			recv:    s.buf,
 		},
 		windowHandler: func(n int) {
 			t.updateWindow(s, uint32(n))
 		},
 	}
+	// Register the stream with loopy.
+	t.controlBuf.put(&registerStream{
+		streamID: s.id,
+		wq:       s.wq,
+	})
 	handle(s)
 	return
 }
@@ -354,53 +429,26 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 // typically run in a separate goroutine.
 // traceCtx attaches trace to ctx and returns the new context.
 func (t *http2Server) HandleStreams(handle func(*Stream), traceCtx func(context.Context, string) context.Context) {
-	// Check the validity of client preface.
-	preface := make([]byte, len(clientPreface))
-	if _, err := io.ReadFull(t.conn, preface); err != nil {
-		// Only log if it isn't a simple tcp accept check (ie: tcp balancer doing open/close socket)
-		if err != io.EOF {
-			errorf("transport: http2Server.HandleStreams failed to receive the preface from client: %v", err)
-		}
-		t.Close()
-		return
-	}
-	if !bytes.Equal(preface, clientPreface) {
-		errorf("transport: http2Server.HandleStreams received bogus greeting from client: %q", preface)
-		t.Close()
-		return
-	}
-
-	frame, err := t.framer.fr.ReadFrame()
-	if err == io.EOF || err == io.ErrUnexpectedEOF {
-		t.Close()
-		return
-	}
-	if err != nil {
-		errorf("transport: http2Server.HandleStreams failed to read initial settings frame: %v", err)
-		t.Close()
-		return
-	}
-	atomic.StoreUint32(&t.activity, 1)
-	sf, ok := frame.(*http2.SettingsFrame)
-	if !ok {
-		errorf("transport: http2Server.HandleStreams saw invalid preface type %T from client", frame)
-		t.Close()
-		return
-	}
-	t.handleSettings(sf)
-
+	defer close(t.readerDone)
 	for {
 		frame, err := t.framer.fr.ReadFrame()
 		atomic.StoreUint32(&t.activity, 1)
 		if err != nil {
 			if se, ok := err.(http2.StreamError); ok {
+				warningf("transport: http2Server.HandleStreams encountered http2.StreamError: %v", se)
 				t.mu.Lock()
 				s := t.activeStreams[se.StreamID]
 				t.mu.Unlock()
 				if s != nil {
-					t.closeStream(s)
+					t.closeStream(s, true, se.Code, nil, false)
+				} else {
+					t.controlBuf.put(&cleanupStream{
+						streamID: se.StreamID,
+						rst:      true,
+						rstCode:  se.Code,
+						onWrite:  func() {},
+					})
 				}
-				t.controlBuf.put(&resetStream{se.StreamID, se.Code})
 				continue
 			}
 			if err == io.EOF || err == io.ErrUnexpectedEOF {
@@ -454,33 +502,20 @@ func (t *http2Server) getStream(f http2.Frame) (*Stream, bool) {
 // of stream if the application is requesting data larger in size than
 // the window.
 func (t *http2Server) adjustWindow(s *Stream, n uint32) {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	if s.state == streamDone {
-		return
-	}
 	if w := s.fc.maybeAdjust(n); w > 0 {
-		if cw := t.fc.resetPendingUpdate(); cw > 0 {
-			t.controlBuf.put(&windowUpdate{0, cw})
-		}
-		t.controlBuf.put(&windowUpdate{s.id, w})
+		t.controlBuf.put(&outgoingWindowUpdate{streamID: s.id, increment: w})
 	}
+
 }
 
 // updateWindow adjusts the inbound quota for the stream and the transport.
 // Window updates will deliver to the controller for sending when
 // the cumulative quota exceeds the corresponding threshold.
 func (t *http2Server) updateWindow(s *Stream, n uint32) {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	if s.state == streamDone {
-		return
-	}
 	if w := s.fc.onRead(n); w > 0 {
-		if cw := t.fc.resetPendingUpdate(); cw > 0 {
-			t.controlBuf.put(&windowUpdate{0, cw})
-		}
-		t.controlBuf.put(&windowUpdate{s.id, w})
+		t.controlBuf.put(&outgoingWindowUpdate{streamID: s.id,
+			increment: w,
+		})
 	}
 }
 
@@ -494,13 +529,15 @@ func (t *http2Server) updateFlowControl(n uint32) {
 	}
 	t.initialWindowSize = int32(n)
 	t.mu.Unlock()
-	t.controlBuf.put(&windowUpdate{0, t.fc.newLimit(n)})
-	t.controlBuf.put(&settings{
-		ack: false,
+	t.controlBuf.put(&outgoingWindowUpdate{
+		streamID:  0,
+		increment: t.fc.newLimit(n),
+	})
+	t.controlBuf.put(&outgoingSettings{
 		ss: []http2.Setting{
 			{
 				ID:  http2.SettingInitialWindowSize,
-				Val: uint32(n),
+				Val: n,
 			},
 		},
 	})
@@ -511,7 +548,7 @@ func (t *http2Server) handleData(f *http2.DataFrame) {
 	size := f.Header().Length
 	var sendBDPPing bool
 	if t.bdpEst != nil {
-		sendBDPPing = t.bdpEst.add(uint32(size))
+		sendBDPPing = t.bdpEst.add(size)
 	}
 	// Decouple connection's flow control from application's read.
 	// An update on connection's flow control should not depend on
@@ -521,23 +558,22 @@ func (t *http2Server) handleData(f *http2.DataFrame) {
 	// Decoupling the connection flow control will prevent other
 	// active(fast) streams from starving in presence of slow or
 	// inactive streams.
-	//
-	// Furthermore, if a bdpPing is being sent out we can piggyback
-	// connection's window update for the bytes we just received.
+	if w := t.fc.onData(size); w > 0 {
+		t.controlBuf.put(&outgoingWindowUpdate{
+			streamID:  0,
+			increment: w,
+		})
+	}
 	if sendBDPPing {
-		if size != 0 { // Could be an empty frame.
-			t.controlBuf.put(&windowUpdate{0, uint32(size)})
+		// Avoid excessive ping detection (e.g. in an L7 proxy)
+		// by sending a window update prior to the BDP ping.
+		if w := t.fc.reset(); w > 0 {
+			t.controlBuf.put(&outgoingWindowUpdate{
+				streamID:  0,
+				increment: w,
+			})
 		}
 		t.controlBuf.put(bdpPing)
-	} else {
-		if err := t.fc.onData(uint32(size)); err != nil {
-			errorf("transport: http2Server %v", err)
-			t.Close()
-			return
-		}
-		if w := t.fc.onRead(uint32(size)); w > 0 {
-			t.controlBuf.put(&windowUpdate{0, w})
-		}
 	}
 	// Select the right stream to dispatch.
 	s, ok := t.getStream(f)
@@ -545,23 +581,15 @@ func (t *http2Server) handleData(f *http2.DataFrame) {
 		return
 	}
 	if size > 0 {
-		s.mu.Lock()
-		if s.state == streamDone {
-			s.mu.Unlock()
-			return
-		}
-		if err := s.fc.onData(uint32(size)); err != nil {
-			s.mu.Unlock()
-			t.closeStream(s)
-			t.controlBuf.put(&resetStream{s.id, http2.ErrCodeFlowControl})
+		if err := s.fc.onData(size); err != nil {
+			t.closeStream(s, true, http2.ErrCodeFlowControl, nil, false)
 			return
 		}
 		if f.Header().Flags.Has(http2.FlagDataPadded) {
-			if w := s.fc.onRead(uint32(size) - uint32(len(f.Data()))); w > 0 {
-				t.controlBuf.put(&windowUpdate{s.id, w})
+			if w := s.fc.onRead(size - uint32(len(f.Data()))); w > 0 {
+				t.controlBuf.put(&outgoingWindowUpdate{s.id, w})
 			}
 		}
-		s.mu.Unlock()
 		// TODO(bradfitz, zhaoq): A copy is required here because there is no
 		// guarantee f.Data() is consumed before the arrival of next frame.
 		// Can this copy be eliminated?
@@ -573,11 +601,7 @@ func (t *http2Server) handleData(f *http2.DataFrame) {
 	}
 	if f.Header().Flags.Has(http2.FlagDataEndStream) {
 		// Received the end of stream from the client.
-		s.mu.Lock()
-		if s.state != streamDone {
-			s.state = streamReadDone
-		}
-		s.mu.Unlock()
+		s.compareAndSwapState(streamActive, streamReadDone)
 		s.write(recvMsg{err: io.EOF})
 	}
 }
@@ -587,7 +611,7 @@ func (t *http2Server) handleRSTStream(f *http2.RSTStreamFrame) {
 	if !ok {
 		return
 	}
-	t.closeStream(s)
+	t.closeStream(s, false, 0, nil, false)
 }
 
 func (t *http2Server) handleSettings(f *http2.SettingsFrame) {
@@ -599,21 +623,9 @@ func (t *http2Server) handleSettings(f *http2.SettingsFrame) {
 		ss = append(ss, s)
 		return nil
 	})
-	t.controlBuf.put(&settings{ack: true, ss: ss})
-}
-
-func (t *http2Server) applySettings(ss []http2.Setting) {
-	for _, s := range ss {
-		if s.ID == http2.SettingInitialWindowSize {
-			t.mu.Lock()
-			for _, stream := range t.activeStreams {
-				stream.sendQuotaPool.addAndUpdate(int(s.Val) - int(t.streamSendQuota))
-			}
-			t.streamSendQuota = s.Val
-			t.mu.Unlock()
-		}
-
-	}
+	t.controlBuf.put(&incomingSettings{
+		ss: ss,
+	})
 }
 
 const (
@@ -666,39 +678,37 @@ func (t *http2Server) handlePing(f *http2.PingFrame) {
 
 	if t.pingStrikes > maxPingStrikes {
 		// Send goaway and close the connection.
-		errorf("transport: Got to too many pings from the client, closing the connection.")
+		errorf("transport: Got too many pings from the client, closing the connection.")
 		t.controlBuf.put(&goAway{code: http2.ErrCodeEnhanceYourCalm, debugData: []byte("too_many_pings"), closeConn: true})
 	}
 }
 
 func (t *http2Server) handleWindowUpdate(f *http2.WindowUpdateFrame) {
-	id := f.Header().StreamID
-	incr := f.Increment
-	if id == 0 {
-		t.sendQuotaPool.add(int(incr))
-		return
-	}
-	if s, ok := t.getStream(f); ok {
-		s.sendQuotaPool.add(int(incr))
+	t.controlBuf.put(&incomingWindowUpdate{
+		streamID:  f.Header().StreamID,
+		increment: f.Increment,
+	})
+}
+
+func appendHeaderFieldsFromMD(headerFields []hpack.HeaderField, md metadata.MD) []hpack.HeaderField {
+	for k, vv := range md {
+		if isReservedHeader(k) {
+			// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
+			continue
+		}
+		for _, v := range vv {
+			headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
+		}
 	}
+	return headerFields
 }
 
 // WriteHeader sends the header metedata md back to the client.
 func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
-	select {
-	case <-s.ctx.Done():
-		return ContextErr(s.ctx.Err())
-	case <-t.ctx.Done():
-		return ErrConnClosing
-	default:
-	}
-
-	s.mu.Lock()
-	if s.headerOk || s.state == streamDone {
-		s.mu.Unlock()
+	if s.updateHeaderSent() || s.getState() == streamDone {
 		return ErrIllegalHeaderWrite
 	}
-	s.headerOk = true
+	s.hdrMu.Lock()
 	if md.Len() > 0 {
 		if s.header.Len() > 0 {
 			s.header = metadata.Join(s.header, md)
@@ -706,37 +716,35 @@ func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
 			s.header = md
 		}
 	}
-	md = s.header
-	s.mu.Unlock()
-	// TODO(mmukhi): Benchmark if the perfomance gets better if count the metadata and other header fields
+	t.writeHeaderLocked(s)
+	s.hdrMu.Unlock()
+	return nil
+}
+
+func (t *http2Server) writeHeaderLocked(s *Stream) {
+	// TODO(mmukhi): Benchmark if the performance gets better if count the metadata and other header fields
 	// first and create a slice of that exact size.
 	headerFields := make([]hpack.HeaderField, 0, 2) // at least :status, content-type will be there if none else.
 	headerFields = append(headerFields, hpack.HeaderField{Name: ":status", Value: "200"})
-	headerFields = append(headerFields, hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
+	headerFields = append(headerFields, hpack.HeaderField{Name: "content-type", Value: contentType(s.contentSubtype)})
 	if s.sendCompress != "" {
 		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-encoding", Value: s.sendCompress})
 	}
-	for k, vv := range md {
-		if isReservedHeader(k) {
-			// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
-			continue
-		}
-		for _, v := range vv {
-			headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
-		}
-	}
+	headerFields = appendHeaderFieldsFromMD(headerFields, s.header)
 	t.controlBuf.put(&headerFrame{
 		streamID:  s.id,
 		hf:        headerFields,
 		endStream: false,
+		onWrite: func() {
+			atomic.StoreUint32(&t.resetPingStrikes, 1)
+		},
 	})
 	if t.stats != nil {
-		outHeader := &stats.OutHeader{
-		//WireLength: // TODO(mmukhi): Revisit this later, if needed.
-		}
+		// Note: WireLength is not set in outHeader.
+		// TODO(mmukhi): Revisit this later, if needed.
+		outHeader := &stats.OutHeader{}
 		t.stats.HandleRPC(s.Context(), outHeader)
 	}
-	return nil
 }
 
 // WriteStatus sends stream status to the client and terminates the stream.
@@ -744,37 +752,20 @@ func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
 // TODO(zhaoq): Now it indicates the end of entire stream. Revisit if early
 // OK is adopted.
 func (t *http2Server) WriteStatus(s *Stream, st *status.Status) error {
-	select {
-	case <-t.ctx.Done():
-		return ErrConnClosing
-	default:
-	}
-
-	var headersSent, hasHeader bool
-	s.mu.Lock()
-	if s.state == streamDone {
-		s.mu.Unlock()
+	if s.getState() == streamDone {
 		return nil
 	}
-	if s.headerOk {
-		headersSent = true
-	}
-	if s.header.Len() > 0 {
-		hasHeader = true
-	}
-	s.mu.Unlock()
-
-	if !headersSent && hasHeader {
-		t.WriteHeader(s, nil)
-		headersSent = true
-	}
-
-	// TODO(mmukhi): Benchmark if the perfomance gets better if count the metadata and other header fields
+	s.hdrMu.Lock()
+	// TODO(mmukhi): Benchmark if the performance gets better if count the metadata and other header fields
 	// first and create a slice of that exact size.
 	headerFields := make([]hpack.HeaderField, 0, 2) // grpc-status and grpc-message will be there if none else.
-	if !headersSent {
-		headerFields = append(headerFields, hpack.HeaderField{Name: ":status", Value: "200"})
-		headerFields = append(headerFields, hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
+	if !s.updateHeaderSent() {                      // No headers have been sent.
+		if len(s.header) > 0 { // Send a separate header frame.
+			t.writeHeaderLocked(s)
+		} else { // Send a trailer only response.
+			headerFields = append(headerFields, hpack.HeaderField{Name: ":status", Value: "200"})
+			headerFields = append(headerFields, hpack.HeaderField{Name: "content-type", Value: contentType(s.contentSubtype)})
+		}
 	}
 	headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-status", Value: strconv.Itoa(int(st.Code()))})
 	headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-message", Value: encodeGrpcMessage(st.Message())})
@@ -783,126 +774,75 @@ func (t *http2Server) WriteStatus(s *Stream, st *status.Status) error {
 		stBytes, err := proto.Marshal(p)
 		if err != nil {
 			// TODO: return error instead, when callers are able to handle it.
-			panic(err)
+			grpclog.Errorf("transport: failed to marshal rpc status: %v, error: %v", p, err)
+		} else {
+			headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-status-details-bin", Value: encodeBinHeader(stBytes)})
 		}
-
-		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-status-details-bin", Value: encodeBinHeader(stBytes)})
 	}
 
 	// Attach the trailer metadata.
-	for k, vv := range s.trailer {
-		// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
-		if isReservedHeader(k) {
-			continue
-		}
-		for _, v := range vv {
-			headerFields = append(headerFields, hpack.HeaderField{Name: k, Value: encodeMetadataHeader(k, v)})
-		}
-	}
-	t.controlBuf.put(&headerFrame{
+	headerFields = appendHeaderFieldsFromMD(headerFields, s.trailer)
+	trailingHeader := &headerFrame{
 		streamID:  s.id,
 		hf:        headerFields,
 		endStream: true,
-	})
+		onWrite: func() {
+			atomic.StoreUint32(&t.resetPingStrikes, 1)
+		},
+	}
+	s.hdrMu.Unlock()
+	t.closeStream(s, false, 0, trailingHeader, true)
 	if t.stats != nil {
 		t.stats.HandleRPC(s.Context(), &stats.OutTrailer{})
 	}
-	t.closeStream(s)
 	return nil
 }
 
 // Write converts the data into HTTP2 data frame and sends it out. Non-nil error
 // is returns if it fails (e.g., framing error, transport error).
-func (t *http2Server) Write(s *Stream, hdr []byte, data []byte, opts *Options) (err error) {
-	select {
-	case <-s.ctx.Done():
-		return ContextErr(s.ctx.Err())
-	case <-t.ctx.Done():
-		return ErrConnClosing
-	default:
-	}
-
-	var writeHeaderFrame bool
-	s.mu.Lock()
-	if s.state == streamDone {
-		s.mu.Unlock()
-		return streamErrorf(codes.Unknown, "the stream has been done")
-	}
-	if !s.headerOk {
-		writeHeaderFrame = true
-	}
-	s.mu.Unlock()
-	if writeHeaderFrame {
-		t.WriteHeader(s, nil)
+func (t *http2Server) Write(s *Stream, hdr []byte, data []byte, opts *Options) error {
+	if !s.isHeaderSent() { // Headers haven't been written yet.
+		if err := t.WriteHeader(s, nil); err != nil {
+			// TODO(mmukhi, dfawley): Make sure this is the right code to return.
+			return streamErrorf(codes.Internal, "transport: %v", err)
+		}
+	} else {
+		// Writing headers checks for this condition.
+		if s.getState() == streamDone {
+			// TODO(mmukhi, dfawley): Should the server write also return io.EOF?
+			s.cancel()
+			select {
+			case <-t.ctx.Done():
+				return ErrConnClosing
+			default:
+			}
+			return ContextErr(s.ctx.Err())
+		}
 	}
-	// Add data to header frame so that we can equally distribute data across frames.
+	// Add some data to header frame so that we can equally distribute bytes across frames.
 	emptyLen := http2MaxFrameLen - len(hdr)
 	if emptyLen > len(data) {
 		emptyLen = len(data)
 	}
 	hdr = append(hdr, data[:emptyLen]...)
 	data = data[emptyLen:]
-	for _, r := range [][]byte{hdr, data} {
-		for len(r) > 0 {
-			size := http2MaxFrameLen
-			// Wait until the stream has some quota to send the data.
-			quotaChan, quotaVer := s.sendQuotaPool.acquireWithVersion()
-			sq, err := wait(s.ctx, t.ctx, nil, nil, quotaChan)
-			if err != nil {
-				return err
-			}
-			// Wait until the transport has some quota to send the data.
-			tq, err := wait(s.ctx, t.ctx, nil, nil, t.sendQuotaPool.acquire())
-			if err != nil {
-				return err
-			}
-			if sq < size {
-				size = sq
-			}
-			if tq < size {
-				size = tq
-			}
-			if size > len(r) {
-				size = len(r)
-			}
-			p := r[:size]
-			ps := len(p)
-			if ps < tq {
-				// Overbooked transport quota. Return it back.
-				t.sendQuotaPool.add(tq - ps)
-			}
-			// Acquire local send quota to be able to write to the controlBuf.
-			ltq, err := wait(s.ctx, t.ctx, nil, nil, s.localSendQuota.acquire())
-			if err != nil {
-				if _, ok := err.(ConnectionError); !ok {
-					t.sendQuotaPool.add(ps)
-				}
-				return err
-			}
-			s.localSendQuota.add(ltq - ps) // It's ok we make this negative.
-			// Reset ping strikes when sending data since this might cause
-			// the peer to send ping.
+	df := &dataFrame{
+		streamID: s.id,
+		h:        hdr,
+		d:        data,
+		onEachWrite: func() {
 			atomic.StoreUint32(&t.resetPingStrikes, 1)
-			success := func() {
-				t.controlBuf.put(&dataFrame{streamID: s.id, endStream: false, d: p, f: func() {
-					s.localSendQuota.add(ps)
-				}})
-				if ps < sq {
-					// Overbooked stream quota. Return it back.
-					s.sendQuotaPool.lockedAdd(sq - ps)
-				}
-				r = r[ps:]
-			}
-			failure := func() {
-				s.sendQuotaPool.lockedAdd(sq)
-			}
-			if !s.sendQuotaPool.compareAndExecute(quotaVer, success, failure) {
-				t.sendQuotaPool.add(ps)
-				s.localSendQuota.add(ps)
-			}
+		},
+	}
+	if err := s.wq.get(int32(len(hdr) + len(data))); err != nil {
+		select {
+		case <-t.ctx.Done():
+			return ErrConnClosing
+		default:
 		}
+		return ContextErr(s.ctx.Err())
 	}
-	return nil
+	return t.controlBuf.put(df)
 }
 
 // keepalive running in a separate goroutine does the following:
@@ -947,7 +887,7 @@ func (t *http2Server) keepalive() {
 				// The connection has been idle for a duration of keepalive.MaxConnectionIdle or more.
 				// Gracefully close the connection.
 				t.drain(http2.ErrCodeNo, []byte{})
-				// Reseting the timer so that the clean-up doesn't deadlock.
+				// Resetting the timer so that the clean-up doesn't deadlock.
 				maxIdle.Reset(infinity)
 				return
 			}
@@ -959,7 +899,7 @@ func (t *http2Server) keepalive() {
 			case <-maxAge.C:
 				// Close the connection after grace period.
 				t.Close()
-				// Reseting the timer so that the clean-up doesn't deadlock.
+				// Resetting the timer so that the clean-up doesn't deadlock.
 				maxAge.Reset(infinity)
 			case <-t.ctx.Done():
 			}
@@ -972,11 +912,16 @@ func (t *http2Server) keepalive() {
 			}
 			if pingSent {
 				t.Close()
-				// Reseting the timer so that the clean-up doesn't deadlock.
+				// Resetting the timer so that the clean-up doesn't deadlock.
 				keepalive.Reset(infinity)
 				return
 			}
 			pingSent = true
+			if channelz.IsOn() {
+				t.czmu.Lock()
+				t.kpCount++
+				t.czmu.Unlock()
+			}
 			t.controlBuf.put(p)
 			keepalive.Reset(t.kp.Timeout)
 		case <-t.ctx.Done():
@@ -985,127 +930,6 @@ func (t *http2Server) keepalive() {
 	}
 }
 
-var goAwayPing = &ping{data: [8]byte{1, 6, 1, 8, 0, 3, 3, 9}}
-
-// TODO(mmukhi): A lot of this code(and code in other places in the tranpsort layer)
-// is duplicated between the client and the server.
-// The transport layer needs to be refactored to take care of this.
-func (t *http2Server) itemHandler(i item) error {
-	switch i := i.(type) {
-	case *dataFrame:
-		if err := t.framer.fr.WriteData(i.streamID, i.endStream, i.d); err != nil {
-			return err
-		}
-		i.f()
-		return nil
-	case *headerFrame:
-		t.hBuf.Reset()
-		for _, f := range i.hf {
-			t.hEnc.WriteField(f)
-		}
-		first := true
-		endHeaders := false
-		for !endHeaders {
-			size := t.hBuf.Len()
-			if size > http2MaxFrameLen {
-				size = http2MaxFrameLen
-			} else {
-				endHeaders = true
-			}
-			var err error
-			if first {
-				first = false
-				err = t.framer.fr.WriteHeaders(http2.HeadersFrameParam{
-					StreamID:      i.streamID,
-					BlockFragment: t.hBuf.Next(size),
-					EndStream:     i.endStream,
-					EndHeaders:    endHeaders,
-				})
-			} else {
-				err = t.framer.fr.WriteContinuation(
-					i.streamID,
-					endHeaders,
-					t.hBuf.Next(size),
-				)
-			}
-			if err != nil {
-				return err
-			}
-		}
-		atomic.StoreUint32(&t.resetPingStrikes, 1)
-		return nil
-	case *windowUpdate:
-		return t.framer.fr.WriteWindowUpdate(i.streamID, i.increment)
-	case *settings:
-		if i.ack {
-			t.applySettings(i.ss)
-			return t.framer.fr.WriteSettingsAck()
-		}
-		return t.framer.fr.WriteSettings(i.ss...)
-	case *resetStream:
-		return t.framer.fr.WriteRSTStream(i.streamID, i.code)
-	case *goAway:
-		t.mu.Lock()
-		if t.state == closing {
-			t.mu.Unlock()
-			// The transport is closing.
-			return fmt.Errorf("transport: Connection closing")
-		}
-		sid := t.maxStreamID
-		if !i.headsUp {
-			// Stop accepting more streams now.
-			t.state = draining
-			t.mu.Unlock()
-			if err := t.framer.fr.WriteGoAway(sid, i.code, i.debugData); err != nil {
-				return err
-			}
-			if i.closeConn {
-				// Abruptly close the connection following the GoAway (via
-				// loopywriter).  But flush out what's inside the buffer first.
-				t.framer.writer.Flush()
-				return fmt.Errorf("transport: Connection closing")
-			}
-			return nil
-		}
-		t.mu.Unlock()
-		// For a graceful close, send out a GoAway with stream ID of MaxUInt32,
-		// Follow that with a ping and wait for the ack to come back or a timer
-		// to expire. During this time accept new streams since they might have
-		// originated before the GoAway reaches the client.
-		// After getting the ack or timer expiration send out another GoAway this
-		// time with an ID of the max stream server intends to process.
-		if err := t.framer.fr.WriteGoAway(math.MaxUint32, http2.ErrCodeNo, []byte{}); err != nil {
-			return err
-		}
-		if err := t.framer.fr.WritePing(false, goAwayPing.data); err != nil {
-			return err
-		}
-		go func() {
-			timer := time.NewTimer(time.Minute)
-			defer timer.Stop()
-			select {
-			case <-t.drainChan:
-			case <-timer.C:
-			case <-t.ctx.Done():
-				return
-			}
-			t.controlBuf.put(&goAway{code: i.code, debugData: i.debugData})
-		}()
-		return nil
-	case *flushIO:
-		return t.framer.writer.Flush()
-	case *ping:
-		if !i.ack {
-			t.bdpEst.timesnap(i.data)
-		}
-		return t.framer.fr.WritePing(i.ack, i.data)
-	default:
-		err := status.Errorf(codes.Internal, "transport: http2Server.controller got unexpected item type %t", i)
-		errorf("%v", err)
-		return err
-	}
-}
-
 // Close starts shutting down the http2Server transport.
 // TODO(zhaoq): Now the destruction is not blocked on any pending streams. This
 // could cause some resource issue. Revisit this later.
@@ -1119,8 +943,12 @@ func (t *http2Server) Close() error {
 	streams := t.activeStreams
 	t.activeStreams = nil
 	t.mu.Unlock()
+	t.controlBuf.finish()
 	t.cancel()
 	err := t.conn.Close()
+	if channelz.IsOn() {
+		channelz.RemoveEntry(t.channelzID)
+	}
 	// Cancel all active streams.
 	for _, s := range streams {
 		s.cancel()
@@ -1134,27 +962,45 @@ func (t *http2Server) Close() error {
 
 // closeStream clears the footprint of a stream when the stream is not needed
 // any more.
-func (t *http2Server) closeStream(s *Stream) {
-	t.mu.Lock()
-	delete(t.activeStreams, s.id)
-	if len(t.activeStreams) == 0 {
-		t.idle = time.Now()
-	}
-	if t.state == draining && len(t.activeStreams) == 0 {
-		defer t.Close()
+func (t *http2Server) closeStream(s *Stream, rst bool, rstCode http2.ErrCode, hdr *headerFrame, eosReceived bool) {
+	if s.swapState(streamDone) == streamDone {
+		// If the stream was already done, return.
+		return
 	}
-	t.mu.Unlock()
 	// In case stream sending and receiving are invoked in separate
 	// goroutines (e.g., bi-directional streaming), cancel needs to be
 	// called to interrupt the potential blocking on other goroutines.
 	s.cancel()
-	s.mu.Lock()
-	if s.state == streamDone {
-		s.mu.Unlock()
-		return
+	cleanup := &cleanupStream{
+		streamID: s.id,
+		rst:      rst,
+		rstCode:  rstCode,
+		onWrite: func() {
+			t.mu.Lock()
+			if t.activeStreams != nil {
+				delete(t.activeStreams, s.id)
+				if len(t.activeStreams) == 0 {
+					t.idle = time.Now()
+				}
+			}
+			t.mu.Unlock()
+			if channelz.IsOn() {
+				t.czmu.Lock()
+				if eosReceived {
+					t.streamsSucceeded++
+				} else {
+					t.streamsFailed++
+				}
+				t.czmu.Unlock()
+			}
+		},
+	}
+	if hdr != nil {
+		hdr.cleanup = cleanup
+		t.controlBuf.put(hdr)
+	} else {
+		t.controlBuf.put(cleanup)
 	}
-	s.state = streamDone
-	s.mu.Unlock()
 }
 
 func (t *http2Server) RemoteAddr() net.Addr {
@@ -1175,7 +1021,115 @@ func (t *http2Server) drain(code http2.ErrCode, debugData []byte) {
 	t.controlBuf.put(&goAway{code: code, debugData: debugData, headsUp: true})
 }
 
-var rgen = rand.New(rand.NewSource(time.Now().UnixNano()))
+var goAwayPing = &ping{data: [8]byte{1, 6, 1, 8, 0, 3, 3, 9}}
+
+// Handles outgoing GoAway and returns true if loopy needs to put itself
+// in draining mode.
+func (t *http2Server) outgoingGoAwayHandler(g *goAway) (bool, error) {
+	t.mu.Lock()
+	if t.state == closing { // TODO(mmukhi): This seems unnecessary.
+		t.mu.Unlock()
+		// The transport is closing.
+		return false, ErrConnClosing
+	}
+	sid := t.maxStreamID
+	if !g.headsUp {
+		// Stop accepting more streams now.
+		t.state = draining
+		if len(t.activeStreams) == 0 {
+			g.closeConn = true
+		}
+		t.mu.Unlock()
+		if err := t.framer.fr.WriteGoAway(sid, g.code, g.debugData); err != nil {
+			return false, err
+		}
+		if g.closeConn {
+			// Abruptly close the connection following the GoAway (via
+			// loopywriter).  But flush out what's inside the buffer first.
+			t.framer.writer.Flush()
+			return false, fmt.Errorf("transport: Connection closing")
+		}
+		return true, nil
+	}
+	t.mu.Unlock()
+	// For a graceful close, send out a GoAway with stream ID of MaxUInt32,
+	// Follow that with a ping and wait for the ack to come back or a timer
+	// to expire. During this time accept new streams since they might have
+	// originated before the GoAway reaches the client.
+	// After getting the ack or timer expiration send out another GoAway this
+	// time with an ID of the max stream server intends to process.
+	if err := t.framer.fr.WriteGoAway(math.MaxUint32, http2.ErrCodeNo, []byte{}); err != nil {
+		return false, err
+	}
+	if err := t.framer.fr.WritePing(false, goAwayPing.data); err != nil {
+		return false, err
+	}
+	go func() {
+		timer := time.NewTimer(time.Minute)
+		defer timer.Stop()
+		select {
+		case <-t.drainChan:
+		case <-timer.C:
+		case <-t.ctx.Done():
+			return
+		}
+		t.controlBuf.put(&goAway{code: g.code, debugData: g.debugData})
+	}()
+	return false, nil
+}
+
+func (t *http2Server) ChannelzMetric() *channelz.SocketInternalMetric {
+	t.czmu.RLock()
+	s := channelz.SocketInternalMetric{
+		StreamsStarted:                   t.streamsStarted,
+		StreamsSucceeded:                 t.streamsSucceeded,
+		StreamsFailed:                    t.streamsFailed,
+		MessagesSent:                     t.msgSent,
+		MessagesReceived:                 t.msgRecv,
+		KeepAlivesSent:                   t.kpCount,
+		LastRemoteStreamCreatedTimestamp: t.lastStreamCreated,
+		LastMessageSentTimestamp:         t.lastMsgSent,
+		LastMessageReceivedTimestamp:     t.lastMsgRecv,
+		LocalFlowControlWindow:           int64(t.fc.getSize()),
+		//socket options
+		LocalAddr:  t.localAddr,
+		RemoteAddr: t.remoteAddr,
+		// Security
+		// RemoteName :
+	}
+	t.czmu.RUnlock()
+	s.RemoteFlowControlWindow = t.getOutFlowWindow()
+	return &s
+}
+
+func (t *http2Server) IncrMsgSent() {
+	t.czmu.Lock()
+	t.msgSent++
+	t.lastMsgSent = time.Now()
+	t.czmu.Unlock()
+}
+
+func (t *http2Server) IncrMsgRecv() {
+	t.czmu.Lock()
+	t.msgRecv++
+	t.lastMsgRecv = time.Now()
+	t.czmu.Unlock()
+}
+
+func (t *http2Server) getOutFlowWindow() int64 {
+	resp := make(chan uint32)
+	timer := time.NewTimer(time.Second)
+	defer timer.Stop()
+	t.controlBuf.put(&outFlowControlSizeRequest{resp})
+	select {
+	case sz := <-resp:
+		return int64(sz)
+	case <-t.ctxDone:
+		return -1
+	case <-timer.C:
+		return -2
+	}
+}
 
 func getJitter(v time.Duration) time.Duration {
 	if v == infinity {
@@ -1183,6 +1137,6 @@ func getJitter(v time.Duration) time.Duration {
 	}
 	// Generate a jitter between +/- 10% of the value.
 	r := int64(v / 10)
-	j := rgen.Int63n(2*r) - r
+	j := grpcrand.Int63n(2*r) - r
 	return time.Duration(j)
 }
diff --git a/vendor/google.golang.org/grpc/transport/http_util.go b/vendor/google.golang.org/grpc/transport/http_util.go
index 39f878c..7d15c7d 100644
--- a/vendor/google.golang.org/grpc/transport/http_util.go
+++ b/vendor/google.golang.org/grpc/transport/http_util.go
@@ -23,12 +23,12 @@ import (
 	"bytes"
 	"encoding/base64"
 	"fmt"
-	"io"
 	"net"
 	"net/http"
 	"strconv"
 	"strings"
 	"time"
+	"unicode/utf8"
 
 	"github.com/golang/protobuf/proto"
 	"golang.org/x/net/http2"
@@ -46,6 +46,12 @@ const (
 	// http2IOBufSize specifies the buffer size for sending frames.
 	defaultWriteBufSize = 32 * 1024
 	defaultReadBufSize  = 32 * 1024
+	// baseContentType is the base content-type for gRPC.  This is a valid
+	// content-type on it's own, but can also include a content-subtype such as
+	// "proto" as a suffix after "+" or ";".  See
+	// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests
+	// for more details.
+	baseContentType = "application/grpc"
 )
 
 var (
@@ -64,7 +70,7 @@ var (
 		http2.ErrCodeConnect:            codes.Internal,
 		http2.ErrCodeEnhanceYourCalm:    codes.ResourceExhausted,
 		http2.ErrCodeInadequateSecurity: codes.PermissionDenied,
-		http2.ErrCodeHTTP11Required:     codes.FailedPrecondition,
+		http2.ErrCodeHTTP11Required:     codes.Internal,
 	}
 	statusCodeConvTab = map[codes.Code]http2.ErrCode{
 		codes.Internal:          http2.ErrCodeInternal,
@@ -111,9 +117,10 @@ type decodeState struct {
 	timeout    time.Duration
 	method     string
 	// key-value metadata map from the peer.
-	mdata      map[string][]string
-	statsTags  []byte
-	statsTrace []byte
+	mdata          map[string][]string
+	statsTags      []byte
+	statsTrace     []byte
+	contentSubtype string
 }
 
 // isReservedHeader checks whether hdr belongs to HTTP2 headers
@@ -125,6 +132,7 @@ func isReservedHeader(hdr string) bool {
 	}
 	switch hdr {
 	case "content-type",
+		"user-agent",
 		"grpc-message-type",
 		"grpc-encoding",
 		"grpc-message",
@@ -138,28 +146,55 @@ func isReservedHeader(hdr string) bool {
 	}
 }
 
-// isWhitelistedPseudoHeader checks whether hdr belongs to HTTP2 pseudoheaders
-// that should be propagated into metadata visible to users.
-func isWhitelistedPseudoHeader(hdr string) bool {
+// isWhitelistedHeader checks whether hdr should be propagated
+// into metadata visible to users.
+func isWhitelistedHeader(hdr string) bool {
 	switch hdr {
-	case ":authority":
+	case ":authority", "user-agent":
 		return true
 	default:
 		return false
 	}
 }
 
-func validContentType(t string) bool {
-	e := "application/grpc"
-	if !strings.HasPrefix(t, e) {
-		return false
+// contentSubtype returns the content-subtype for the given content-type.  The
+// given content-type must be a valid content-type that starts with
+// "application/grpc". A content-subtype will follow "application/grpc" after a
+// "+" or ";". See
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+//
+// If contentType is not a valid content-type for gRPC, the boolean
+// will be false, otherwise true. If content-type == "application/grpc",
+// "application/grpc+", or "application/grpc;", the boolean will be true,
+// but no content-subtype will be returned.
+//
+// contentType is assumed to be lowercase already.
+func contentSubtype(contentType string) (string, bool) {
+	if contentType == baseContentType {
+		return "", true
+	}
+	if !strings.HasPrefix(contentType, baseContentType) {
+		return "", false
+	}
+	// guaranteed since != baseContentType and has baseContentType prefix
+	switch contentType[len(baseContentType)] {
+	case '+', ';':
+		// this will return true for "application/grpc+" or "application/grpc;"
+		// which the previous validContentType function tested to be valid, so we
+		// just say that no content-subtype is specified in this case
+		return contentType[len(baseContentType)+1:], true
+	default:
+		return "", false
 	}
-	// Support variations on the content-type
-	// (e.g. "application/grpc+blah", "application/grpc;blah").
-	if len(t) > len(e) && t[len(e)] != '+' && t[len(e)] != ';' {
-		return false
+}
+
+// contentSubtype is assumed to be lowercase
+func contentType(contentSubtype string) string {
+	if contentSubtype == "" {
+		return baseContentType
 	}
-	return true
+	return baseContentType + "+" + contentSubtype
 }
 
 func (d *decodeState) status() *status.Status {
@@ -228,9 +263,9 @@ func (d *decodeState) decodeResponseHeader(frame *http2.MetaHeadersFrame) error
 	// gRPC status doesn't exist and http status is OK.
 	// Set rawStatusCode to be unknown and return nil error.
 	// So that, if the stream has ended this Unknown status
-	// will be propogated to the user.
+	// will be propagated to the user.
 	// Otherwise, it will be ignored. In which case, status from
-	// a later trailer, that has StreamEnded flag set, is propogated.
+	// a later trailer, that has StreamEnded flag set, is propagated.
 	code := int(codes.Unknown)
 	d.rawStatusCode = &code
 	return nil
@@ -247,9 +282,16 @@ func (d *decodeState) addMetadata(k, v string) {
 func (d *decodeState) processHeaderField(f hpack.HeaderField) error {
 	switch f.Name {
 	case "content-type":
-		if !validContentType(f.Value) {
-			return streamErrorf(codes.FailedPrecondition, "transport: received the unexpected content-type %q", f.Value)
+		contentSubtype, validContentType := contentSubtype(f.Value)
+		if !validContentType {
+			return streamErrorf(codes.Internal, "transport: received the unexpected content-type %q", f.Value)
 		}
+		d.contentSubtype = contentSubtype
+		// TODO: do we want to propagate the whole content-type in the metadata,
+		// or come up with a way to just propagate the content-subtype if it was set?
+		// ie {"content-type": "application/grpc+proto"} or {"content-subtype": "proto"}
+		// in the metadata?
+		d.addMetadata(f.Name, f.Value)
 	case "grpc-encoding":
 		d.encoding = f.Value
 	case "grpc-status":
@@ -299,7 +341,7 @@ func (d *decodeState) processHeaderField(f hpack.HeaderField) error {
 		d.statsTrace = v
 		d.addMetadata(f.Name, string(v))
 	default:
-		if isReservedHeader(f.Name) && !isWhitelistedPseudoHeader(f.Name) {
+		if isReservedHeader(f.Name) && !isWhitelistedHeader(f.Name) {
 			break
 		}
 		v, err := decodeMetadataHeader(f.Name, f.Value)
@@ -307,7 +349,7 @@ func (d *decodeState) processHeaderField(f hpack.HeaderField) error {
 			errorf("Failed to decode metadata header (%q, %q): %v", f.Name, f.Value, err)
 			return nil
 		}
-		d.addMetadata(f.Name, string(v))
+		d.addMetadata(f.Name, v)
 	}
 	return nil
 }
@@ -396,16 +438,17 @@ func decodeTimeout(s string) (time.Duration, error) {
 
 const (
 	spaceByte   = ' '
-	tildaByte   = '~'
+	tildeByte   = '~'
 	percentByte = '%'
 )
 
 // encodeGrpcMessage is used to encode status code in header field
-// "grpc-message".
-// It checks to see if each individual byte in msg is an
-// allowable byte, and then either percent encoding or passing it through.
-// When percent encoding, the byte is converted into hexadecimal notation
-// with a '%' prepended.
+// "grpc-message". It does percent encoding and also replaces invalid utf-8
+// characters with Unicode replacement character.
+//
+// It checks to see if each individual byte in msg is an allowable byte, and
+// then either percent encoding or passing it through. When percent encoding,
+// the byte is converted into hexadecimal notation with a '%' prepended.
 func encodeGrpcMessage(msg string) string {
 	if msg == "" {
 		return ""
@@ -413,7 +456,7 @@ func encodeGrpcMessage(msg string) string {
 	lenMsg := len(msg)
 	for i := 0; i < lenMsg; i++ {
 		c := msg[i]
-		if !(c >= spaceByte && c < tildaByte && c != percentByte) {
+		if !(c >= spaceByte && c <= tildeByte && c != percentByte) {
 			return encodeGrpcMessageUnchecked(msg)
 		}
 	}
@@ -422,14 +465,26 @@ func encodeGrpcMessage(msg string) string {
 
 func encodeGrpcMessageUnchecked(msg string) string {
 	var buf bytes.Buffer
-	lenMsg := len(msg)
-	for i := 0; i < lenMsg; i++ {
-		c := msg[i]
-		if c >= spaceByte && c < tildaByte && c != percentByte {
-			buf.WriteByte(c)
-		} else {
-			buf.WriteString(fmt.Sprintf("%%%02X", c))
+	for len(msg) > 0 {
+		r, size := utf8.DecodeRuneInString(msg)
+		for _, b := range []byte(string(r)) {
+			if size > 1 {
+				// If size > 1, r is not ascii. Always do percent encoding.
+				buf.WriteString(fmt.Sprintf("%%%02X", b))
+				continue
+			}
+
+			// The for loop is necessary even if size == 1. r could be
+			// utf8.RuneError.
+			//
+			// fmt.Sprintf("%%%02X", utf8.RuneError) gives "%FFFD".
+			if b >= spaceByte && b <= tildeByte && b != percentByte {
+				buf.WriteByte(b)
+			} else {
+				buf.WriteString(fmt.Sprintf("%%%02X", b))
+			}
 		}
+		msg = msg[size:]
 	}
 	return buf.String()
 }
@@ -468,19 +523,67 @@ func decodeGrpcMessageUnchecked(msg string) string {
 	return buf.String()
 }
 
+type bufWriter struct {
+	buf       []byte
+	offset    int
+	batchSize int
+	conn      net.Conn
+	err       error
+
+	onFlush func()
+}
+
+func newBufWriter(conn net.Conn, batchSize int) *bufWriter {
+	return &bufWriter{
+		buf:       make([]byte, batchSize*2),
+		batchSize: batchSize,
+		conn:      conn,
+	}
+}
+
+func (w *bufWriter) Write(b []byte) (n int, err error) {
+	if w.err != nil {
+		return 0, w.err
+	}
+	for len(b) > 0 {
+		nn := copy(w.buf[w.offset:], b)
+		b = b[nn:]
+		w.offset += nn
+		n += nn
+		if w.offset >= w.batchSize {
+			err = w.Flush()
+		}
+	}
+	return n, err
+}
+
+func (w *bufWriter) Flush() error {
+	if w.err != nil {
+		return w.err
+	}
+	if w.offset == 0 {
+		return nil
+	}
+	if w.onFlush != nil {
+		w.onFlush()
+	}
+	_, w.err = w.conn.Write(w.buf[:w.offset])
+	w.offset = 0
+	return w.err
+}
+
 type framer struct {
-	numWriters int32
-	reader     io.Reader
-	writer     *bufio.Writer
-	fr         *http2.Framer
+	writer *bufWriter
+	fr     *http2.Framer
 }
 
 func newFramer(conn net.Conn, writeBufferSize, readBufferSize int) *framer {
+	r := bufio.NewReaderSize(conn, readBufferSize)
+	w := newBufWriter(conn, writeBufferSize)
 	f := &framer{
-		reader: bufio.NewReaderSize(conn, readBufferSize),
-		writer: bufio.NewWriterSize(conn, writeBufferSize),
+		writer: w,
+		fr:     http2.NewFramer(w, r),
 	}
-	f.fr = http2.NewFramer(f.writer, f.reader)
 	// Opt-in to Frame reuse API on framer to reduce garbage.
 	// Frames aren't safe to read from after a subsequent call to ReadFrame.
 	f.fr.SetReuseFrames()
diff --git a/vendor/google.golang.org/grpc/transport/transport.go b/vendor/google.golang.org/grpc/transport/transport.go
index 2cf9bd3..f51f878 100644
--- a/vendor/google.golang.org/grpc/transport/transport.go
+++ b/vendor/google.golang.org/grpc/transport/transport.go
@@ -17,19 +17,19 @@
  */
 
 // Package transport defines and implements message oriented communication
-// channel to complete various transactions (e.g., an RPC).
-package transport // import "google.golang.org/grpc/transport"
+// channel to complete various transactions (e.g., an RPC).  It is meant for
+// grpc-internal usage and is not intended to be imported directly by users.
+package transport // externally used as import "google.golang.org/grpc/transport"
 
 import (
-	stdctx "context"
+	"errors"
 	"fmt"
 	"io"
 	"net"
 	"sync"
-	"time"
+	"sync/atomic"
 
 	"golang.org/x/net/context"
-	"golang.org/x/net/http2"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/keepalive"
@@ -58,6 +58,7 @@ type recvBuffer struct {
 	c       chan recvMsg
 	mu      sync.Mutex
 	backlog []recvMsg
+	err     error
 }
 
 func newRecvBuffer() *recvBuffer {
@@ -69,6 +70,13 @@ func newRecvBuffer() *recvBuffer {
 
 func (b *recvBuffer) put(r recvMsg) {
 	b.mu.Lock()
+	if b.err != nil {
+		b.mu.Unlock()
+		// An error had occurred earlier, don't accept more
+		// data or errors.
+		return
+	}
+	b.err = r.err
 	if len(b.backlog) == 0 {
 		select {
 		case b.c <- r:
@@ -102,14 +110,15 @@ func (b *recvBuffer) get() <-chan recvMsg {
 	return b.c
 }
 
+//
 // recvBufferReader implements io.Reader interface to read the data from
 // recvBuffer.
 type recvBufferReader struct {
-	ctx    context.Context
-	goAway chan struct{}
-	recv   *recvBuffer
-	last   []byte // Stores the remaining data in the previous calls.
-	err    error
+	ctx     context.Context
+	ctxDone <-chan struct{} // cache of ctx.Done() (for performance).
+	recv    *recvBuffer
+	last    []byte // Stores the remaining data in the previous calls.
+	err     error
 }
 
 // Read reads the next len(p) bytes from last. If last is drained, it tries to
@@ -131,10 +140,8 @@ func (r *recvBufferReader) read(p []byte) (n int, err error) {
 		return copied, nil
 	}
 	select {
-	case <-r.ctx.Done():
+	case <-r.ctxDone:
 		return 0, ContextErr(r.ctx.Err())
-	case <-r.goAway:
-		return 0, ErrStreamDrain
 	case m := <-r.recv.get():
 		r.recv.load()
 		if m.err != nil {
@@ -146,61 +153,7 @@ func (r *recvBufferReader) read(p []byte) (n int, err error) {
 	}
 }
 
-// All items in an out of a controlBuffer should be the same type.
-type item interface {
-	item()
-}
-
-// controlBuffer is an unbounded channel of item.
-type controlBuffer struct {
-	c       chan item
-	mu      sync.Mutex
-	backlog []item
-}
-
-func newControlBuffer() *controlBuffer {
-	b := &controlBuffer{
-		c: make(chan item, 1),
-	}
-	return b
-}
-
-func (b *controlBuffer) put(r item) {
-	b.mu.Lock()
-	if len(b.backlog) == 0 {
-		select {
-		case b.c <- r:
-			b.mu.Unlock()
-			return
-		default:
-		}
-	}
-	b.backlog = append(b.backlog, r)
-	b.mu.Unlock()
-}
-
-func (b *controlBuffer) load() {
-	b.mu.Lock()
-	if len(b.backlog) > 0 {
-		select {
-		case b.c <- b.backlog[0]:
-			b.backlog[0] = nil
-			b.backlog = b.backlog[1:]
-		default:
-		}
-	}
-	b.mu.Unlock()
-}
-
-// get returns the channel that receives an item in the buffer.
-//
-// Upon receipt of an item, the caller should call load to send another
-// item onto the channel if there is any.
-func (b *controlBuffer) get() <-chan item {
-	return b.c
-}
-
-type streamState uint8
+type streamState uint32
 
 const (
 	streamActive    streamState = iota
@@ -211,66 +164,93 @@ const (
 
 // Stream represents an RPC in the transport layer.
 type Stream struct {
-	id uint32
-	// nil for client side Stream.
-	st ServerTransport
-	// ctx is the associated context of the stream.
-	ctx context.Context
-	// cancel is always nil for client side Stream.
-	cancel context.CancelFunc
-	// done is closed when the final status arrives.
-	done chan struct{}
-	// goAway is closed when the server sent GoAways signal before this stream was initiated.
-	goAway chan struct{}
-	// method records the associated RPC method of the stream.
-	method       string
+	id           uint32
+	st           ServerTransport    // nil for client side Stream
+	ctx          context.Context    // the associated context of the stream
+	cancel       context.CancelFunc // always nil for client side Stream
+	done         chan struct{}      // closed at the end of stream to unblock writers. On the client side.
+	ctxDone      <-chan struct{}    // same as done chan but for server side. Cache of ctx.Done() (for performance)
+	method       string             // the associated RPC method of the stream
 	recvCompress string
 	sendCompress string
 	buf          *recvBuffer
 	trReader     io.Reader
 	fc           *inFlow
 	recvQuota    uint32
-
-	// TODO: Remote this unused variable.
-	// The accumulated inbound quota pending for window update.
-	updateQuota uint32
+	wq           *writeQuota
 
 	// Callback to state application's intentions to read data. This
-	// is used to adjust flow control, if need be.
+	// is used to adjust flow control, if needed.
 	requestRead func(int)
 
-	sendQuotaPool  *quotaPool
-	localSendQuota *quotaPool
-	// Close headerChan to indicate the end of reception of header metadata.
-	headerChan chan struct{}
-	// header caches the received header metadata.
-	header metadata.MD
-	// The key-value map of trailer metadata.
-	trailer metadata.MD
-
-	mu sync.RWMutex // guard the following
-	// headerOK becomes true from the first header is about to send.
-	headerOk bool
-	state    streamState
-	// true iff headerChan is closed. Used to avoid closing headerChan
-	// multiple times.
-	headerDone bool
-	// the status error received from the server.
+	headerChan chan struct{} // closed to indicate the end of header metadata.
+	headerDone uint32        // set when headerChan is closed. Used to avoid closing headerChan multiple times.
+
+	// hdrMu protects header and trailer metadata on the server-side.
+	hdrMu   sync.Mutex
+	header  metadata.MD // the received header metadata.
+	trailer metadata.MD // the key-value map of trailer metadata.
+
+	// On the server-side, headerSent is atomically set to 1 when the headers are sent out.
+	headerSent uint32
+
+	state streamState
+
+	// On client-side it is the status error received from the server.
+	// On server-side it is unused.
 	status *status.Status
-	// rstStream indicates whether a RST_STREAM frame needs to be sent
-	// to the server to signify that this stream is closing.
-	rstStream bool
-	// rstError is the error that needs to be sent along with the RST_STREAM frame.
-	rstError http2.ErrCode
-	// bytesSent and bytesReceived indicates whether any bytes have been sent or
-	// received on this stream.
-	bytesSent     bool
-	bytesReceived bool
+
+	bytesReceived uint32 // indicates whether any bytes have been received on this stream
+	unprocessed   uint32 // set if the server sends a refused stream or GOAWAY including this stream
+
+	// contentSubtype is the content-subtype for requests.
+	// this must be lowercase or the behavior is undefined.
+	contentSubtype string
+}
+
+// isHeaderSent is only valid on the server-side.
+func (s *Stream) isHeaderSent() bool {
+	return atomic.LoadUint32(&s.headerSent) == 1
+}
+
+// updateHeaderSent updates headerSent and returns true
+// if it was alreay set. It is valid only on server-side.
+func (s *Stream) updateHeaderSent() bool {
+	return atomic.SwapUint32(&s.headerSent, 1) == 1
+}
+
+func (s *Stream) swapState(st streamState) streamState {
+	return streamState(atomic.SwapUint32((*uint32)(&s.state), uint32(st)))
+}
+
+func (s *Stream) compareAndSwapState(oldState, newState streamState) bool {
+	return atomic.CompareAndSwapUint32((*uint32)(&s.state), uint32(oldState), uint32(newState))
+}
+
+func (s *Stream) getState() streamState {
+	return streamState(atomic.LoadUint32((*uint32)(&s.state)))
+}
+
+func (s *Stream) waitOnHeader() error {
+	if s.headerChan == nil {
+		// On the server headerChan is always nil since a stream originates
+		// only after having received headers.
+		return nil
+	}
+	select {
+	case <-s.ctx.Done():
+		return ContextErr(s.ctx.Err())
+	case <-s.headerChan:
+		return nil
+	}
 }
 
 // RecvCompress returns the compression algorithm applied to the inbound
 // message. It is empty string if there is no compression applied.
 func (s *Stream) RecvCompress() string {
+	if err := s.waitOnHeader(); err != nil {
+		return ""
+	}
 	return s.recvCompress
 }
 
@@ -285,28 +265,17 @@ func (s *Stream) Done() <-chan struct{} {
 	return s.done
 }
 
-// GoAway returns a channel which is closed when the server sent GoAways signal
-// before this stream was initiated.
-func (s *Stream) GoAway() <-chan struct{} {
-	return s.goAway
-}
-
 // Header acquires the key-value pairs of header metadata once it
 // is available. It blocks until i) the metadata is ready or ii) there is no
 // header metadata or iii) the stream is canceled/expired.
 func (s *Stream) Header() (metadata.MD, error) {
-	var err error
-	select {
-	case <-s.ctx.Done():
-		err = ContextErr(s.ctx.Err())
-	case <-s.goAway:
-		err = ErrStreamDrain
-	case <-s.headerChan:
-		return s.header.Copy(), nil
-	}
+	err := s.waitOnHeader()
 	// Even if the stream is closed, header is returned if available.
 	select {
 	case <-s.headerChan:
+		if s.header == nil {
+			return nil, nil
+		}
 		return s.header.Copy(), nil
 	default:
 	}
@@ -316,10 +285,10 @@ func (s *Stream) Header() (metadata.MD, error) {
 // Trailer returns the cached trailer metedata. Note that if it is not called
 // after the entire stream is done, it could return an empty MD. Client
 // side only.
+// It can be safely read only after stream has ended that is either read
+// or write have returned io.EOF.
 func (s *Stream) Trailer() metadata.MD {
-	s.mu.RLock()
 	c := s.trailer.Copy()
-	s.mu.RUnlock()
 	return c
 }
 
@@ -329,6 +298,15 @@ func (s *Stream) ServerTransport() ServerTransport {
 	return s.st
 }
 
+// ContentSubtype returns the content-subtype for a request. For example, a
+// content-subtype of "proto" will result in a content-type of
+// "application/grpc+proto". This will always be lowercase.  See
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+func (s *Stream) ContentSubtype() string {
+	return s.contentSubtype
+}
+
 // Context returns the context of the stream.
 func (s *Stream) Context() context.Context {
 	return s.ctx
@@ -340,36 +318,49 @@ func (s *Stream) Method() string {
 }
 
 // Status returns the status received from the server.
+// Status can be read safely only after the stream has ended,
+// that is, read or write has returned io.EOF.
 func (s *Stream) Status() *status.Status {
 	return s.status
 }
 
 // SetHeader sets the header metadata. This can be called multiple times.
 // Server side only.
+// This should not be called in parallel to other data writes.
 func (s *Stream) SetHeader(md metadata.MD) error {
-	s.mu.Lock()
-	if s.headerOk || s.state == streamDone {
-		s.mu.Unlock()
-		return ErrIllegalHeaderWrite
-	}
 	if md.Len() == 0 {
-		s.mu.Unlock()
 		return nil
 	}
+	if s.isHeaderSent() || s.getState() == streamDone {
+		return ErrIllegalHeaderWrite
+	}
+	s.hdrMu.Lock()
 	s.header = metadata.Join(s.header, md)
-	s.mu.Unlock()
+	s.hdrMu.Unlock()
 	return nil
 }
 
+// SendHeader sends the given header metadata. The given metadata is
+// combined with any metadata set by previous calls to SetHeader and
+// then written to the transport stream.
+func (s *Stream) SendHeader(md metadata.MD) error {
+	t := s.ServerTransport()
+	return t.WriteHeader(s, md)
+}
+
 // SetTrailer sets the trailer metadata which will be sent with the RPC status
 // by the server. This can be called multiple times. Server side only.
+// This should not be called parallel to other data writes.
 func (s *Stream) SetTrailer(md metadata.MD) error {
 	if md.Len() == 0 {
 		return nil
 	}
-	s.mu.Lock()
+	if s.getState() == streamDone {
+		return ErrIllegalHeaderWrite
+	}
+	s.hdrMu.Lock()
 	s.trailer = metadata.Join(s.trailer, md)
-	s.mu.Unlock()
+	s.hdrMu.Unlock()
 	return nil
 }
 
@@ -409,28 +400,15 @@ func (t *transportReader) Read(p []byte) (n int, err error) {
 	return
 }
 
-// finish sets the stream's state and status, and closes the done channel.
-// s.mu must be held by the caller.  st must always be non-nil.
-func (s *Stream) finish(st *status.Status) {
-	s.status = st
-	s.state = streamDone
-	close(s.done)
-}
-
-// BytesSent indicates whether any bytes have been sent on this stream.
-func (s *Stream) BytesSent() bool {
-	s.mu.Lock()
-	bs := s.bytesSent
-	s.mu.Unlock()
-	return bs
-}
-
 // BytesReceived indicates whether any bytes have been received on this stream.
 func (s *Stream) BytesReceived() bool {
-	s.mu.Lock()
-	br := s.bytesReceived
-	s.mu.Unlock()
-	return br
+	return atomic.LoadUint32(&s.bytesReceived) == 1
+}
+
+// Unprocessed indicates whether the server did not process this stream --
+// i.e. it sent a refused stream or GOAWAY including this stream ID.
+func (s *Stream) Unprocessed() bool {
+	return atomic.LoadUint32(&s.unprocessed) == 1
 }
 
 // GoString is implemented by Stream so context.String() won't
@@ -439,21 +417,6 @@ func (s *Stream) GoString() string {
 	return fmt.Sprintf("<stream: %p, %v>", s, s.method)
 }
 
-// The key to save transport.Stream in the context.
-type streamKey struct{}
-
-// newContextWithStream creates a new context from ctx and attaches stream
-// to it.
-func newContextWithStream(ctx context.Context, stream *Stream) context.Context {
-	return context.WithValue(ctx, streamKey{}, stream)
-}
-
-// StreamFromContext returns the stream saved in ctx.
-func StreamFromContext(ctx context.Context) (s *Stream, ok bool) {
-	s, ok = ctx.Value(streamKey{}).(*Stream)
-	return
-}
-
 // state of transport
 type transportState int
 
@@ -475,6 +438,7 @@ type ServerConfig struct {
 	InitialConnWindowSize int32
 	WriteBufferSize       int
 	ReadBufferSize        int
+	ChannelzParentID      int64
 }
 
 // NewServerTransport creates a ServerTransport with conn or non-nil error
@@ -510,18 +474,21 @@ type ConnectOptions struct {
 	WriteBufferSize int
 	// ReadBufferSize sets the size of read buffer, which in turn determines how much data can be read at most for one read syscall.
 	ReadBufferSize int
+	// ChannelzParentID sets the addrConn id which initiate the creation of this client transport.
+	ChannelzParentID int64
 }
 
 // TargetInfo contains the information of the target such as network address and metadata.
 type TargetInfo struct {
-	Addr     string
-	Metadata interface{}
+	Addr      string
+	Metadata  interface{}
+	Authority string
 }
 
 // NewClientTransport establishes the transport with the required ConnectOptions
 // and returns it to the caller.
-func NewClientTransport(ctx context.Context, target TargetInfo, opts ConnectOptions, timeout time.Duration) (ClientTransport, error) {
-	return newHTTP2Client(ctx, target, opts, timeout)
+func NewClientTransport(connectCtx, ctx context.Context, target TargetInfo, opts ConnectOptions, onSuccess func()) (ClientTransport, error) {
+	return newHTTP2Client(connectCtx, ctx, target, opts, onSuccess)
 }
 
 // Options provides additional hints and information for message
@@ -545,10 +512,6 @@ type CallHdr struct {
 	// Method specifies the operation to perform.
 	Method string
 
-	// RecvCompress specifies the compression algorithm applied on
-	// inbound messages.
-	RecvCompress string
-
 	// SendCompress specifies the compression algorithm applied on
 	// outbound message.
 	SendCompress string
@@ -563,6 +526,14 @@ type CallHdr struct {
 	// for performance purposes.
 	// If it's false, new stream will never be flushed.
 	Flush bool
+
+	// ContentSubtype specifies the content-subtype for a request. For example, a
+	// content-subtype of "proto" will result in a content-type of
+	// "application/grpc+proto". The value of ContentSubtype must be all
+	// lowercase, otherwise the behavior is undefined. See
+	// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests
+	// for more details.
+	ContentSubtype string
 }
 
 // ClientTransport is the common interface for all gRPC client-side transport
@@ -604,6 +575,12 @@ type ClientTransport interface {
 
 	// GetGoAwayReason returns the reason why GoAway frame was received.
 	GetGoAwayReason() GoAwayReason
+
+	// IncrMsgSent increments the number of message sent through this transport.
+	IncrMsgSent()
+
+	// IncrMsgRecv increments the number of message received through this transport.
+	IncrMsgRecv()
 }
 
 // ServerTransport is the common interface for all gRPC server-side transport
@@ -637,6 +614,12 @@ type ServerTransport interface {
 
 	// Drain notifies the client this ServerTransport stops accepting new RPCs.
 	Drain()
+
+	// IncrMsgSent increments the number of message sent through this transport.
+	IncrMsgSent()
+
+	// IncrMsgRecv increments the number of message received through this transport.
+	IncrMsgRecv()
 }
 
 // streamErrorf creates an StreamError with the specified error code and description.
@@ -686,9 +669,16 @@ func (e ConnectionError) Origin() error {
 var (
 	// ErrConnClosing indicates that the transport is closing.
 	ErrConnClosing = connectionErrorf(true, nil, "transport is closing")
-	// ErrStreamDrain indicates that the stream is rejected by the server because
-	// the server stops accepting new RPCs.
-	ErrStreamDrain = streamErrorf(codes.Unavailable, "the server stops accepting new RPCs")
+	// errStreamDrain indicates that the stream is rejected because the
+	// connection is draining. This could be caused by goaway or balancer
+	// removing the address.
+	errStreamDrain = streamErrorf(codes.Unavailable, "the connection is draining")
+	// errStreamDone is returned from write at the client side to indiacte application
+	// layer of an error.
+	errStreamDone = errors.New("the stream is done")
+	// StatusGoAway indicates that the server sent a GOAWAY that included this
+	// stream's ID in unprocessed RPCs.
+	statusGoAway = status.New(codes.Unavailable, "the stream is rejected because server is draining the connection")
 )
 
 // TODO: See if we can replace StreamError with status package errors.
@@ -703,80 +693,16 @@ func (e StreamError) Error() string {
 	return fmt.Sprintf("stream error: code = %s desc = %q", e.Code, e.Desc)
 }
 
-// wait blocks until it can receive from one of the provided contexts or
-// channels.  ctx is the context of the RPC, tctx is the context of the
-// transport, done is a channel closed to indicate the end of the RPC, goAway
-// is a channel closed to indicate a GOAWAY was received, and proceed is a
-// quota channel, whose received value is returned from this function if none
-// of the other signals occur first.
-func wait(ctx, tctx context.Context, done, goAway <-chan struct{}, proceed <-chan int) (int, error) {
-	select {
-	case <-ctx.Done():
-		return 0, ContextErr(ctx.Err())
-	case <-done:
-		return 0, io.EOF
-	case <-goAway:
-		return 0, ErrStreamDrain
-	case <-tctx.Done():
-		return 0, ErrConnClosing
-	case i := <-proceed:
-		return i, nil
-	}
-}
-
-// ContextErr converts the error from context package into a StreamError.
-func ContextErr(err error) StreamError {
-	switch err {
-	case context.DeadlineExceeded, stdctx.DeadlineExceeded:
-		return streamErrorf(codes.DeadlineExceeded, "%v", err)
-	case context.Canceled, stdctx.Canceled:
-		return streamErrorf(codes.Canceled, "%v", err)
-	}
-	return streamErrorf(codes.Internal, "Unexpected error from context packet: %v", err)
-}
-
 // GoAwayReason contains the reason for the GoAway frame received.
 type GoAwayReason uint8
 
 const (
-	// Invalid indicates that no GoAway frame is received.
-	Invalid GoAwayReason = 0
-	// NoReason is the default value when GoAway frame is received.
-	NoReason GoAwayReason = 1
-	// TooManyPings indicates that a GoAway frame with ErrCodeEnhanceYourCalm
-	// was received and that the debug data said "too_many_pings".
-	TooManyPings GoAwayReason = 2
+	// GoAwayInvalid indicates that no GoAway frame is received.
+	GoAwayInvalid GoAwayReason = 0
+	// GoAwayNoReason is the default value when GoAway frame is received.
+	GoAwayNoReason GoAwayReason = 1
+	// GoAwayTooManyPings indicates that a GoAway frame with
+	// ErrCodeEnhanceYourCalm was received and that the debug data said
+	// "too_many_pings".
+	GoAwayTooManyPings GoAwayReason = 2
 )
-
-// loopyWriter is run in a separate go routine. It is the single code path that will
-// write data on wire.
-func loopyWriter(ctx context.Context, cbuf *controlBuffer, handler func(item) error) {
-	for {
-		select {
-		case i := <-cbuf.get():
-			cbuf.load()
-			if err := handler(i); err != nil {
-				return
-			}
-		case <-ctx.Done():
-			return
-		}
-	hasData:
-		for {
-			select {
-			case i := <-cbuf.get():
-				cbuf.load()
-				if err := handler(i); err != nil {
-					return
-				}
-			case <-ctx.Done():
-				return
-			default:
-				if err := handler(&flushIO{}); err != nil {
-					return
-				}
-				break hasData
-			}
-		}
-	}
-}
diff --git a/vendor/google.golang.org/grpc/version.go b/vendor/google.golang.org/grpc/version.go
new file mode 100644
index 0000000..9e85edf
--- /dev/null
+++ b/vendor/google.golang.org/grpc/version.go
@@ -0,0 +1,22 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+// Version is the current grpc version.
+const Version = "1.14.0-dev"
diff --git a/vendor/google.golang.org/grpc/vet.sh b/vendor/google.golang.org/grpc/vet.sh
index 72ef329..079bc28 100755
--- a/vendor/google.golang.org/grpc/vet.sh
+++ b/vendor/google.golang.org/grpc/vet.sh
@@ -1,5 +1,10 @@
 #!/bin/bash
 
+if [[ `uname -a` = *"Darwin"* ]]; then
+  echo "It seems you are running on Mac. This script does not work on Mac. See https://github.com/grpc/grpc-go/issues/2047"
+  exit 1
+fi
+
 set -ex  # Exit on error; debugging enabled.
 set -o pipefail  # Fail a pipe if any sub-command fails.
 
@@ -8,12 +13,6 @@ die() {
   exit 1
 }
 
-# TODO: Remove this check and the mangling below once "context" is imported
-# directly.
-if git status --porcelain | read; then
-  die "Uncommitted or untracked files found; commit changes first"
-fi
-
 PATH="$GOPATH/bin:$GOROOT/bin:$PATH"
 
 # Check proto in manual runs or cron runs.
@@ -28,8 +27,8 @@ if [ "$1" = "-install" ]; then
     github.com/golang/lint/golint \
     golang.org/x/tools/cmd/goimports \
     honnef.co/go/tools/cmd/staticcheck \
-    github.com/golang/protobuf/protoc-gen-go \
-    golang.org/x/tools/cmd/stringer
+    github.com/client9/misspell/cmd/misspell \
+    github.com/golang/protobuf/protoc-gen-go
   if [[ "$check_proto" = "true" ]]; then
     if [[ "$TRAVIS" = "true" ]]; then
       PROTOBUF_VERSION=3.3.0
@@ -48,10 +47,18 @@ elif [[ "$#" -ne 0 ]]; then
   die "Unknown argument(s): $*"
 fi
 
+# TODO: Remove this check and the mangling below once "context" is imported
+# directly.
+if git status --porcelain | read; then
+  die "Uncommitted or untracked files found; commit changes first"
+fi
+
 git ls-files "*.go" | xargs grep -L "\(Copyright [0-9]\{4,\} gRPC authors\)\|DO NOT EDIT" 2>&1 | tee /dev/stderr | (! read)
+git ls-files "*.go" | xargs grep -l '"unsafe"' 2>&1 | (! grep -v '_test.go') | tee /dev/stderr | (! read)
+git ls-files "*.go" | xargs grep -l '"math/rand"' 2>&1 | (! grep -v '^examples\|^stress\|grpcrand') | tee /dev/stderr | (! read)
 gofmt -s -d -l . 2>&1 | tee /dev/stderr | (! read)
 goimports -l . 2>&1 | tee /dev/stderr | (! read)
-golint ./... 2>&1 | (grep -vE "(_mock|_string|\.pb)\.go:" || true) | tee /dev/stderr | (! read)
+golint ./... 2>&1 | (grep -vE "(_mock|\.pb)\.go:" || true) | tee /dev/stderr | (! read)
 
 # Undo any edits made by this script.
 cleanup() {
@@ -64,7 +71,7 @@ trap cleanup EXIT
 git ls-files "*.go" | xargs sed -i 's:"golang.org/x/net/context":"context":'
 set +o pipefail
 # TODO: Stop filtering pb.go files once golang/protobuf#214 is fixed.
-go tool vet -all . 2>&1 | grep -vF '.pb.go:' | tee /dev/stderr | (! read)
+go tool vet -all . 2>&1 | grep -vE '(clientconn|transport\/transport_test).go:.*cancel (function|var)' | grep -vF '.pb.go:' | tee /dev/stderr | (! read)
 set -o pipefail
 git reset --hard HEAD
 
@@ -75,4 +82,13 @@ if [[ "$check_proto" = "true" ]]; then
 fi
 
 # TODO(menghanl): fix errors in transport_test.
-staticcheck -ignore google.golang.org/grpc/transport/transport_test.go:SA2002 ./...
+staticcheck -ignore '
+google.golang.org/grpc/transport/transport_test.go:SA2002
+google.golang.org/grpc/benchmark/benchmain/main.go:SA1019
+google.golang.org/grpc/stats/stats_test.go:SA1019
+google.golang.org/grpc/test/end2end_test.go:SA1019
+google.golang.org/grpc/balancer_test.go:SA1019
+google.golang.org/grpc/balancer.go:SA1019
+google.golang.org/grpc/clientconn_test.go:SA1019
+' ./...
+misspell -error .