update vendor

30 files changed, 11853 insertions, 0 deletions

diff --git a/vendor/golang.org/x/net/http2/Dockerfile b/vendor/golang.org/x/net/http2/Dockerfile
new file mode 100644
index 0000000..53fc525
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/Dockerfile
@@ -0,0 +1,51 @@
+#
+# This Dockerfile builds a recent curl with HTTP/2 client support, using
+# a recent nghttp2 build.
+#
+# See the Makefile for how to tag it. If Docker and that image is found, the
+# Go tests use this curl binary for integration tests.
+#
+
+FROM ubuntu:trusty
+
+RUN apt-get update && \
+    apt-get upgrade -y && \
+    apt-get install -y git-core build-essential wget
+
+RUN apt-get install -y --no-install-recommends \
+       autotools-dev libtool pkg-config zlib1g-dev \
+       libcunit1-dev libssl-dev libxml2-dev libevent-dev \
+       automake autoconf
+
+# The list of packages nghttp2 recommends for h2load:
+RUN apt-get install -y --no-install-recommends make binutils \
+        autoconf automake autotools-dev \
+        libtool pkg-config zlib1g-dev libcunit1-dev libssl-dev libxml2-dev \
+        libev-dev libevent-dev libjansson-dev libjemalloc-dev \
+        cython python3.4-dev python-setuptools
+
+# Note: setting NGHTTP2_VER before the git clone, so an old git clone isn't cached:
+ENV NGHTTP2_VER 895da9a
+RUN cd /root && git clone https://github.com/tatsuhiro-t/nghttp2.git
+
+WORKDIR /root/nghttp2
+RUN git reset --hard $NGHTTP2_VER
+RUN autoreconf -i
+RUN automake
+RUN autoconf
+RUN ./configure
+RUN make
+RUN make install
+
+WORKDIR /root
+RUN wget http://curl.haxx.se/download/curl-7.45.0.tar.gz
+RUN tar -zxvf curl-7.45.0.tar.gz
+WORKDIR /root/curl-7.45.0
+RUN ./configure --with-ssl --with-nghttp2=/usr/local
+RUN make
+RUN make install
+RUN ldconfig
+
+CMD ["-h"]
+ENTRYPOINT ["/usr/local/bin/curl"]
+
diff --git a/vendor/golang.org/x/net/http2/Makefile b/vendor/golang.org/x/net/http2/Makefile
new file mode 100644
index 0000000..55fd826
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/Makefile
@@ -0,0 +1,3 @@
+curlimage:
+	docker build -t gohttp2/curl .
+
diff --git a/vendor/golang.org/x/net/http2/README b/vendor/golang.org/x/net/http2/README
new file mode 100644
index 0000000..360d5aa
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/README
@@ -0,0 +1,20 @@
+This is a work-in-progress HTTP/2 implementation for Go.
+
+It will eventually live in the Go standard library and won't require
+any changes to your code to use.  It will just be automatic.
+
+Status:
+
+* The server support is pretty good. A few things are missing
+  but are being worked on.
+* The client work has just started but shares a lot of code
+  is coming along much quicker.
+
+Docs are at https://godoc.org/golang.org/x/net/http2
+
+Demo test server at https://http2.golang.org/
+
+Help & bug reports welcome!
+
+Contributing: https://golang.org/doc/contribute.html
+Bugs:         https://golang.org/issue/new?title=x/net/http2:+
diff --git a/vendor/golang.org/x/net/http2/client_conn_pool.go b/vendor/golang.org/x/net/http2/client_conn_pool.go
new file mode 100644
index 0000000..8cb3eaa
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/client_conn_pool.go
@@ -0,0 +1,246 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Transport code's client connection pooling.
+
+package http2
+
+import (
+	"crypto/tls"
+	"net/http"
+	"sync"
+)
+
+// ClientConnPool manages a pool of HTTP/2 client connections.
+type ClientConnPool interface {
+	GetClientConn(req *http.Request, addr string) (*ClientConn, error)
+	MarkDead(*ClientConn)
+}
+
+// clientConnPoolIdleCloser is the interface implemented by ClientConnPool
+// implementations which can close their idle connections.
+type clientConnPoolIdleCloser interface {
+	ClientConnPool
+	closeIdleConnections()
+}
+
+var (
+	_ clientConnPoolIdleCloser = (*clientConnPool)(nil)
+	_ clientConnPoolIdleCloser = noDialClientConnPool{}
+)
+
+// TODO: use singleflight for dialing and addConnCalls?
+type clientConnPool struct {
+	t *Transport
+
+	mu sync.Mutex // TODO: maybe switch to RWMutex
+	// TODO: add support for sharing conns based on cert names
+	// (e.g. share conn for googleapis.com and appspot.com)
+	conns        map[string][]*ClientConn // key is host:port
+	dialing      map[string]*dialCall     // currently in-flight dials
+	keys         map[*ClientConn][]string
+	addConnCalls map[string]*addConnCall // in-flight addConnIfNeede calls
+}
+
+func (p *clientConnPool) GetClientConn(req *http.Request, addr string) (*ClientConn, error) {
+	return p.getClientConn(req, addr, dialOnMiss)
+}
+
+const (
+	dialOnMiss   = true
+	noDialOnMiss = false
+)
+
+func (p *clientConnPool) getClientConn(_ *http.Request, addr string, dialOnMiss bool) (*ClientConn, error) {
+	p.mu.Lock()
+	for _, cc := range p.conns[addr] {
+		if cc.CanTakeNewRequest() {
+			p.mu.Unlock()
+			return cc, nil
+		}
+	}
+	if !dialOnMiss {
+		p.mu.Unlock()
+		return nil, ErrNoCachedConn
+	}
+	call := p.getStartDialLocked(addr)
+	p.mu.Unlock()
+	<-call.done
+	return call.res, call.err
+}
+
+// dialCall is an in-flight Transport dial call to a host.
+type dialCall struct {
+	p    *clientConnPool
+	done chan struct{} // closed when done
+	res  *ClientConn   // valid after done is closed
+	err  error         // valid after done is closed
+}
+
+// requires p.mu is held.
+func (p *clientConnPool) getStartDialLocked(addr string) *dialCall {
+	if call, ok := p.dialing[addr]; ok {
+		// A dial is already in-flight. Don't start another.
+		return call
+	}
+	call := &dialCall{p: p, done: make(chan struct{})}
+	if p.dialing == nil {
+		p.dialing = make(map[string]*dialCall)
+	}
+	p.dialing[addr] = call
+	go call.dial(addr)
+	return call
+}
+
+// run in its own goroutine.
+func (c *dialCall) dial(addr string) {
+	c.res, c.err = c.p.t.dialClientConn(addr)
+	close(c.done)
+
+	c.p.mu.Lock()
+	delete(c.p.dialing, addr)
+	if c.err == nil {
+		c.p.addConnLocked(addr, c.res)
+	}
+	c.p.mu.Unlock()
+}
+
+// addConnIfNeeded makes a NewClientConn out of c if a connection for key doesn't
+// already exist. It coalesces concurrent calls with the same key.
+// This is used by the http1 Transport code when it creates a new connection. Because
+// the http1 Transport doesn't de-dup TCP dials to outbound hosts (because it doesn't know
+// the protocol), it can get into a situation where it has multiple TLS connections.
+// This code decides which ones live or die.
+// The return value used is whether c was used.
+// c is never closed.
+func (p *clientConnPool) addConnIfNeeded(key string, t *Transport, c *tls.Conn) (used bool, err error) {
+	p.mu.Lock()
+	for _, cc := range p.conns[key] {
+		if cc.CanTakeNewRequest() {
+			p.mu.Unlock()
+			return false, nil
+		}
+	}
+	call, dup := p.addConnCalls[key]
+	if !dup {
+		if p.addConnCalls == nil {
+			p.addConnCalls = make(map[string]*addConnCall)
+		}
+		call = &addConnCall{
+			p:    p,
+			done: make(chan struct{}),
+		}
+		p.addConnCalls[key] = call
+		go call.run(t, key, c)
+	}
+	p.mu.Unlock()
+
+	<-call.done
+	if call.err != nil {
+		return false, call.err
+	}
+	return !dup, nil
+}
+
+type addConnCall struct {
+	p    *clientConnPool
+	done chan struct{} // closed when done
+	err  error
+}
+
+func (c *addConnCall) run(t *Transport, key string, tc *tls.Conn) {
+	cc, err := t.NewClientConn(tc)
+
+	p := c.p
+	p.mu.Lock()
+	if err != nil {
+		c.err = err
+	} else {
+		p.addConnLocked(key, cc)
+	}
+	delete(p.addConnCalls, key)
+	p.mu.Unlock()
+	close(c.done)
+}
+
+func (p *clientConnPool) addConn(key string, cc *ClientConn) {
+	p.mu.Lock()
+	p.addConnLocked(key, cc)
+	p.mu.Unlock()
+}
+
+// p.mu must be held
+func (p *clientConnPool) addConnLocked(key string, cc *ClientConn) {
+	for _, v := range p.conns[key] {
+		if v == cc {
+			return
+		}
+	}
+	if p.conns == nil {
+		p.conns = make(map[string][]*ClientConn)
+	}
+	if p.keys == nil {
+		p.keys = make(map[*ClientConn][]string)
+	}
+	p.conns[key] = append(p.conns[key], cc)
+	p.keys[cc] = append(p.keys[cc], key)
+}
+
+func (p *clientConnPool) MarkDead(cc *ClientConn) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	for _, key := range p.keys[cc] {
+		vv, ok := p.conns[key]
+		if !ok {
+			continue
+		}
+		newList := filterOutClientConn(vv, cc)
+		if len(newList) > 0 {
+			p.conns[key] = newList
+		} else {
+			delete(p.conns, key)
+		}
+	}
+	delete(p.keys, cc)
+}
+
+func (p *clientConnPool) closeIdleConnections() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	// TODO: don't close a cc if it was just added to the pool
+	// milliseconds ago and has never been used. There's currently
+	// a small race window with the HTTP/1 Transport's integration
+	// where it can add an idle conn just before using it, and
+	// somebody else can concurrently call CloseIdleConns and
+	// break some caller's RoundTrip.
+	for _, vv := range p.conns {
+		for _, cc := range vv {
+			cc.closeIfIdle()
+		}
+	}
+}
+
+func filterOutClientConn(in []*ClientConn, exclude *ClientConn) []*ClientConn {
+	out := in[:0]
+	for _, v := range in {
+		if v != exclude {
+			out = append(out, v)
+		}
+	}
+	// If we filtered it out, zero out the last item to prevent
+	// the GC from seeing it.
+	if len(in) != len(out) {
+		in[len(in)-1] = nil
+	}
+	return out
+}
+
+// noDialClientConnPool is an implementation of http2.ClientConnPool
+// which never dials.  We let the HTTP/1.1 client dial and use its TLS
+// connection instead.
+type noDialClientConnPool struct{ *clientConnPool }
+
+func (p noDialClientConnPool) GetClientConn(req *http.Request, addr string) (*ClientConn, error) {
+	return p.getClientConn(req, addr, noDialOnMiss)
+}
diff --git a/vendor/golang.org/x/net/http2/configure_transport.go b/vendor/golang.org/x/net/http2/configure_transport.go
new file mode 100644
index 0000000..d87ba0f
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/configure_transport.go
@@ -0,0 +1,80 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.6
+
+package http2
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net/http"
+)
+
+func configureTransport(t1 *http.Transport) (*Transport, error) {
+	connPool := new(clientConnPool)
+	t2 := &Transport{
+		ConnPool: noDialClientConnPool{connPool},
+		t1:       t1,
+	}
+	connPool.t = t2
+	if err := registerHTTPSProtocol(t1, noDialH2RoundTripper{t2}); err != nil {
+		return nil, err
+	}
+	if t1.TLSClientConfig == nil {
+		t1.TLSClientConfig = new(tls.Config)
+	}
+	if !strSliceContains(t1.TLSClientConfig.NextProtos, "h2") {
+		t1.TLSClientConfig.NextProtos = append([]string{"h2"}, t1.TLSClientConfig.NextProtos...)
+	}
+	if !strSliceContains(t1.TLSClientConfig.NextProtos, "http/1.1") {
+		t1.TLSClientConfig.NextProtos = append(t1.TLSClientConfig.NextProtos, "http/1.1")
+	}
+	upgradeFn := func(authority string, c *tls.Conn) http.RoundTripper {
+		addr := authorityAddr(authority)
+		if used, err := connPool.addConnIfNeeded(addr, t2, c); err != nil {
+			go c.Close()
+			return erringRoundTripper{err}
+		} else if !used {
+			// Turns out we don't need this c.
+			// For example, two goroutines made requests to the same host
+			// at the same time, both kicking off TCP dials. (since protocol
+			// was unknown)
+			go c.Close()
+		}
+		return t2
+	}
+	if m := t1.TLSNextProto; len(m) == 0 {
+		t1.TLSNextProto = map[string]func(string, *tls.Conn) http.RoundTripper{
+			"h2": upgradeFn,
+		}
+	} else {
+		m["h2"] = upgradeFn
+	}
+	return t2, nil
+}
+
+// registerHTTPSProtocol calls Transport.RegisterProtocol but
+// convering panics into errors.
+func registerHTTPSProtocol(t *http.Transport, rt http.RoundTripper) (err error) {
+	defer func() {
+		if e := recover(); e != nil {
+			err = fmt.Errorf("%v", e)
+		}
+	}()
+	t.RegisterProtocol("https", rt)
+	return nil
+}
+
+// noDialH2RoundTripper is a RoundTripper which only tries to complete the request
+// if there's already has a cached connection to the host.
+type noDialH2RoundTripper struct{ t *Transport }
+
+func (rt noDialH2RoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	res, err := rt.t.RoundTrip(req)
+	if err == ErrNoCachedConn {
+		return nil, http.ErrSkipAltProtocol
+	}
+	return res, err
+}
diff --git a/vendor/golang.org/x/net/http2/errors.go b/vendor/golang.org/x/net/http2/errors.go
new file mode 100644
index 0000000..71a4e29
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/errors.go
@@ -0,0 +1,122 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http2
+
+import (
+	"errors"
+	"fmt"
+)
+
+// An ErrCode is an unsigned 32-bit error code as defined in the HTTP/2 spec.
+type ErrCode uint32
+
+const (
+	ErrCodeNo                 ErrCode = 0x0
+	ErrCodeProtocol           ErrCode = 0x1
+	ErrCodeInternal           ErrCode = 0x2
+	ErrCodeFlowControl        ErrCode = 0x3
+	ErrCodeSettingsTimeout    ErrCode = 0x4
+	ErrCodeStreamClosed       ErrCode = 0x5
+	ErrCodeFrameSize          ErrCode = 0x6
+	ErrCodeRefusedStream      ErrCode = 0x7
+	ErrCodeCancel             ErrCode = 0x8
+	ErrCodeCompression        ErrCode = 0x9
+	ErrCodeConnect            ErrCode = 0xa
+	ErrCodeEnhanceYourCalm    ErrCode = 0xb
+	ErrCodeInadequateSecurity ErrCode = 0xc
+	ErrCodeHTTP11Required     ErrCode = 0xd
+)
+
+var errCodeName = map[ErrCode]string{
+	ErrCodeNo:                 "NO_ERROR",
+	ErrCodeProtocol:           "PROTOCOL_ERROR",
+	ErrCodeInternal:           "INTERNAL_ERROR",
+	ErrCodeFlowControl:        "FLOW_CONTROL_ERROR",
+	ErrCodeSettingsTimeout:    "SETTINGS_TIMEOUT",
+	ErrCodeStreamClosed:       "STREAM_CLOSED",
+	ErrCodeFrameSize:          "FRAME_SIZE_ERROR",
+	ErrCodeRefusedStream:      "REFUSED_STREAM",
+	ErrCodeCancel:             "CANCEL",
+	ErrCodeCompression:        "COMPRESSION_ERROR",
+	ErrCodeConnect:            "CONNECT_ERROR",
+	ErrCodeEnhanceYourCalm:    "ENHANCE_YOUR_CALM",
+	ErrCodeInadequateSecurity: "INADEQUATE_SECURITY",
+	ErrCodeHTTP11Required:     "HTTP_1_1_REQUIRED",
+}
+
+func (e ErrCode) String() string {
+	if s, ok := errCodeName[e]; ok {
+		return s
+	}
+	return fmt.Sprintf("unknown error code 0x%x", uint32(e))
+}
+
+// ConnectionError is an error that results in the termination of the
+// entire connection.
+type ConnectionError ErrCode
+
+func (e ConnectionError) Error() string { return fmt.Sprintf("connection error: %s", ErrCode(e)) }
+
+// StreamError is an error that only affects one stream within an
+// HTTP/2 connection.
+type StreamError struct {
+	StreamID uint32
+	Code     ErrCode
+}
+
+func (e StreamError) Error() string {
+	return fmt.Sprintf("stream error: stream ID %d; %v", e.StreamID, e.Code)
+}
+
+// 6.9.1 The Flow Control Window
+// "If a sender receives a WINDOW_UPDATE that causes a flow control
+// window to exceed this maximum it MUST terminate either the stream
+// or the connection, as appropriate. For streams, [...]; for the
+// connection, a GOAWAY frame with a FLOW_CONTROL_ERROR code."
+type goAwayFlowError struct{}
+
+func (goAwayFlowError) Error() string { return "connection exceeded flow control window size" }
+
+// connErrorReason wraps a ConnectionError with an informative error about why it occurs.
+
+// Errors of this type are only returned by the frame parser functions
+// and converted into ConnectionError(ErrCodeProtocol).
+type connError struct {
+	Code   ErrCode
+	Reason string
+}
+
+func (e connError) Error() string {
+	return fmt.Sprintf("http2: connection error: %v: %v", e.Code, e.Reason)
+}
+
+type pseudoHeaderError string
+
+func (e pseudoHeaderError) Error() string {
+	return fmt.Sprintf("invalid pseudo-header %q", string(e))
+}
+
+type duplicatePseudoHeaderError string
+
+func (e duplicatePseudoHeaderError) Error() string {
+	return fmt.Sprintf("duplicate pseudo-header %q", string(e))
+}
+
+type headerFieldNameError string
+
+func (e headerFieldNameError) Error() string {
+	return fmt.Sprintf("invalid header field name %q", string(e))
+}
+
+type headerFieldValueError string
+
+func (e headerFieldValueError) Error() string {
+	return fmt.Sprintf("invalid header field value %q", string(e))
+}
+
+var (
+	errMixPseudoHeaderTypes = errors.New("mix of request and response pseudo headers")
+	errPseudoAfterRegular   = errors.New("pseudo header field after regular")
+)
diff --git a/vendor/golang.org/x/net/http2/fixed_buffer.go b/vendor/golang.org/x/net/http2/fixed_buffer.go
new file mode 100644
index 0000000..47da0f0
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/fixed_buffer.go
@@ -0,0 +1,60 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http2
+
+import (
+	"errors"
+)
+
+// fixedBuffer is an io.ReadWriter backed by a fixed size buffer.
+// It never allocates, but moves old data as new data is written.
+type fixedBuffer struct {
+	buf  []byte
+	r, w int
+}
+
+var (
+	errReadEmpty = errors.New("read from empty fixedBuffer")
+	errWriteFull = errors.New("write on full fixedBuffer")
+)
+
+// Read copies bytes from the buffer into p.
+// It is an error to read when no data is available.
+func (b *fixedBuffer) Read(p []byte) (n int, err error) {
+	if b.r == b.w {
+		return 0, errReadEmpty
+	}
+	n = copy(p, b.buf[b.r:b.w])
+	b.r += n
+	if b.r == b.w {
+		b.r = 0
+		b.w = 0
+	}
+	return n, nil
+}
+
+// Len returns the number of bytes of the unread portion of the buffer.
+func (b *fixedBuffer) Len() int {
+	return b.w - b.r
+}
+
+// Write copies bytes from p into the buffer.
+// It is an error to write more data than the buffer can hold.
+func (b *fixedBuffer) Write(p []byte) (n int, err error) {
+	// Slide existing data to beginning.
+	if b.r > 0 && len(p) > len(b.buf)-b.w {
+		copy(b.buf, b.buf[b.r:b.w])
+		b.w -= b.r
+		b.r = 0
+	}
+
+	// Write new data.
+	n = copy(b.buf[b.w:], p)
+	b.w += n
+	if n < len(p) {
+		err = errWriteFull
+	}
+	return n, err
+}
diff --git a/vendor/golang.org/x/net/http2/flow.go b/vendor/golang.org/x/net/http2/flow.go
new file mode 100644
index 0000000..957de25
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/flow.go
@@ -0,0 +1,50 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Flow control
+
+package http2
+
+// flow is the flow control window's size.
+type flow struct {
+	// n is the number of DATA bytes we're allowed to send.
+	// A flow is kept both on a conn and a per-stream.
+	n int32
+
+	// conn points to the shared connection-level flow that is
+	// shared by all streams on that conn. It is nil for the flow
+	// that's on the conn directly.
+	conn *flow
+}
+
+func (f *flow) setConnFlow(cf *flow) { f.conn = cf }
+
+func (f *flow) available() int32 {
+	n := f.n
+	if f.conn != nil && f.conn.n < n {
+		n = f.conn.n
+	}
+	return n
+}
+
+func (f *flow) take(n int32) {
+	if n > f.available() {
+		panic("internal error: took too much")
+	}
+	f.n -= n
+	if f.conn != nil {
+		f.conn.n -= n
+	}
+}
+
+// add adds n bytes (positive or negative) to the flow control window.
+// It returns false if the sum would exceed 2^31-1.
+func (f *flow) add(n int32) bool {
+	remain := (1<<31 - 1) - f.n
+	if n > remain {
+		return false
+	}
+	f.n += n
+	return true
+}
diff --git a/vendor/golang.org/x/net/http2/frame.go b/vendor/golang.org/x/net/http2/frame.go
new file mode 100644
index 0000000..88067dc
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/frame.go
@@ -0,0 +1,1507 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http2
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"strings"
+	"sync"
+
+	"golang.org/x/net/http2/hpack"
+	"golang.org/x/net/lex/httplex"
+)
+
+const frameHeaderLen = 9
+
+var padZeros = make([]byte, 255) // zeros for padding
+
+// A FrameType is a registered frame type as defined in
+// http://http2.github.io/http2-spec/#rfc.section.11.2
+type FrameType uint8
+
+const (
+	FrameData         FrameType = 0x0
+	FrameHeaders      FrameType = 0x1
+	FramePriority     FrameType = 0x2
+	FrameRSTStream    FrameType = 0x3
+	FrameSettings     FrameType = 0x4
+	FramePushPromise  FrameType = 0x5
+	FramePing         FrameType = 0x6
+	FrameGoAway       FrameType = 0x7
+	FrameWindowUpdate FrameType = 0x8
+	FrameContinuation FrameType = 0x9
+)
+
+var frameName = map[FrameType]string{
+	FrameData:         "DATA",
+	FrameHeaders:      "HEADERS",
+	FramePriority:     "PRIORITY",
+	FrameRSTStream:    "RST_STREAM",
+	FrameSettings:     "SETTINGS",
+	FramePushPromise:  "PUSH_PROMISE",
+	FramePing:         "PING",
+	FrameGoAway:       "GOAWAY",
+	FrameWindowUpdate: "WINDOW_UPDATE",
+	FrameContinuation: "CONTINUATION",
+}
+
+func (t FrameType) String() string {
+	if s, ok := frameName[t]; ok {
+		return s
+	}
+	return fmt.Sprintf("UNKNOWN_FRAME_TYPE_%d", uint8(t))
+}
+
+// Flags is a bitmask of HTTP/2 flags.
+// The meaning of flags varies depending on the frame type.
+type Flags uint8
+
+// Has reports whether f contains all (0 or more) flags in v.
+func (f Flags) Has(v Flags) bool {
+	return (f & v) == v
+}
+
+// Frame-specific FrameHeader flag bits.
+const (
+	// Data Frame
+	FlagDataEndStream Flags = 0x1
+	FlagDataPadded    Flags = 0x8
+
+	// Headers Frame
+	FlagHeadersEndStream  Flags = 0x1
+	FlagHeadersEndHeaders Flags = 0x4
+	FlagHeadersPadded     Flags = 0x8
+	FlagHeadersPriority   Flags = 0x20
+
+	// Settings Frame
+	FlagSettingsAck Flags = 0x1
+
+	// Ping Frame
+	FlagPingAck Flags = 0x1
+
+	// Continuation Frame
+	FlagContinuationEndHeaders Flags = 0x4
+
+	FlagPushPromiseEndHeaders Flags = 0x4
+	FlagPushPromisePadded     Flags = 0x8
+)
+
+var flagName = map[FrameType]map[Flags]string{
+	FrameData: {
+		FlagDataEndStream: "END_STREAM",
+		FlagDataPadded:    "PADDED",
+	},
+	FrameHeaders: {
+		FlagHeadersEndStream:  "END_STREAM",
+		FlagHeadersEndHeaders: "END_HEADERS",
+		FlagHeadersPadded:     "PADDED",
+		FlagHeadersPriority:   "PRIORITY",
+	},
+	FrameSettings: {
+		FlagSettingsAck: "ACK",
+	},
+	FramePing: {
+		FlagPingAck: "ACK",
+	},
+	FrameContinuation: {
+		FlagContinuationEndHeaders: "END_HEADERS",
+	},
+	FramePushPromise: {
+		FlagPushPromiseEndHeaders: "END_HEADERS",
+		FlagPushPromisePadded:     "PADDED",
+	},
+}
+
+// a frameParser parses a frame given its FrameHeader and payload
+// bytes. The length of payload will always equal fh.Length (which
+// might be 0).
+type frameParser func(fh FrameHeader, payload []byte) (Frame, error)
+
+var frameParsers = map[FrameType]frameParser{
+	FrameData:         parseDataFrame,
+	FrameHeaders:      parseHeadersFrame,
+	FramePriority:     parsePriorityFrame,
+	FrameRSTStream:    parseRSTStreamFrame,
+	FrameSettings:     parseSettingsFrame,
+	FramePushPromise:  parsePushPromise,
+	FramePing:         parsePingFrame,
+	FrameGoAway:       parseGoAwayFrame,
+	FrameWindowUpdate: parseWindowUpdateFrame,
+	FrameContinuation: parseContinuationFrame,
+}
+
+func typeFrameParser(t FrameType) frameParser {
+	if f := frameParsers[t]; f != nil {
+		return f
+	}
+	return parseUnknownFrame
+}
+
+// A FrameHeader is the 9 byte header of all HTTP/2 frames.
+//
+// See http://http2.github.io/http2-spec/#FrameHeader
+type FrameHeader struct {
+	valid bool // caller can access []byte fields in the Frame
+
+	// Type is the 1 byte frame type. There are ten standard frame
+	// types, but extension frame types may be written by WriteRawFrame
+	// and will be returned by ReadFrame (as UnknownFrame).
+	Type FrameType
+
+	// Flags are the 1 byte of 8 potential bit flags per frame.
+	// They are specific to the frame type.
+	Flags Flags
+
+	// Length is the length of the frame, not including the 9 byte header.
+	// The maximum size is one byte less than 16MB (uint24), but only
+	// frames up to 16KB are allowed without peer agreement.
+	Length uint32
+
+	// StreamID is which stream this frame is for. Certain frames
+	// are not stream-specific, in which case this field is 0.
+	StreamID uint32
+}
+
+// Header returns h. It exists so FrameHeaders can be embedded in other
+// specific frame types and implement the Frame interface.
+func (h FrameHeader) Header() FrameHeader { return h }
+
+func (h FrameHeader) String() string {
+	var buf bytes.Buffer
+	buf.WriteString("[FrameHeader ")
+	h.writeDebug(&buf)
+	buf.WriteByte(']')
+	return buf.String()
+}
+
+func (h FrameHeader) writeDebug(buf *bytes.Buffer) {
+	buf.WriteString(h.Type.String())
+	if h.Flags != 0 {
+		buf.WriteString(" flags=")
+		set := 0
+		for i := uint8(0); i < 8; i++ {
+			if h.Flags&(1<<i) == 0 {
+				continue
+			}
+			set++
+			if set > 1 {
+				buf.WriteByte('|')
+			}
+			name := flagName[h.Type][Flags(1<<i)]
+			if name != "" {
+				buf.WriteString(name)
+			} else {
+				fmt.Fprintf(buf, "0x%x", 1<<i)
+			}
+		}
+	}
+	if h.StreamID != 0 {
+		fmt.Fprintf(buf, " stream=%d", h.StreamID)
+	}
+	fmt.Fprintf(buf, " len=%d", h.Length)
+}
+
+func (h *FrameHeader) checkValid() {
+	if !h.valid {
+		panic("Frame accessor called on non-owned Frame")
+	}
+}
+
+func (h *FrameHeader) invalidate() { h.valid = false }
+
+// frame header bytes.
+// Used only by ReadFrameHeader.
+var fhBytes = sync.Pool{
+	New: func() interface{} {
+		buf := make([]byte, frameHeaderLen)
+		return &buf
+	},
+}
+
+// ReadFrameHeader reads 9 bytes from r and returns a FrameHeader.
+// Most users should use Framer.ReadFrame instead.
+func ReadFrameHeader(r io.Reader) (FrameHeader, error) {
+	bufp := fhBytes.Get().(*[]byte)
+	defer fhBytes.Put(bufp)
+	return readFrameHeader(*bufp, r)
+}
+
+func readFrameHeader(buf []byte, r io.Reader) (FrameHeader, error) {
+	_, err := io.ReadFull(r, buf[:frameHeaderLen])
+	if err != nil {
+		return FrameHeader{}, err
+	}
+	return FrameHeader{
+		Length:   (uint32(buf[0])<<16 | uint32(buf[1])<<8 | uint32(buf[2])),
+		Type:     FrameType(buf[3]),
+		Flags:    Flags(buf[4]),
+		StreamID: binary.BigEndian.Uint32(buf[5:]) & (1<<31 - 1),
+		valid:    true,
+	}, nil
+}
+
+// A Frame is the base interface implemented by all frame types.
+// Callers will generally type-assert the specific frame type:
+// *HeadersFrame, *SettingsFrame, *WindowUpdateFrame, etc.
+//
+// Frames are only valid until the next call to Framer.ReadFrame.
+type Frame interface {
+	Header() FrameHeader
+
+	// invalidate is called by Framer.ReadFrame to make this
+	// frame's buffers as being invalid, since the subsequent
+	// frame will reuse them.
+	invalidate()
+}
+
+// A Framer reads and writes Frames.
+type Framer struct {
+	r         io.Reader
+	lastFrame Frame
+	errDetail error
+
+	// lastHeaderStream is non-zero if the last frame was an
+	// unfinished HEADERS/CONTINUATION.
+	lastHeaderStream uint32
+
+	maxReadSize uint32
+	headerBuf   [frameHeaderLen]byte
+
+	// TODO: let getReadBuf be configurable, and use a less memory-pinning
+	// allocator in server.go to minimize memory pinned for many idle conns.
+	// Will probably also need to make frame invalidation have a hook too.
+	getReadBuf func(size uint32) []byte
+	readBuf    []byte // cache for default getReadBuf
+
+	maxWriteSize uint32 // zero means unlimited; TODO: implement
+
+	w    io.Writer
+	wbuf []byte
+
+	// AllowIllegalWrites permits the Framer's Write methods to
+	// write frames that do not conform to the HTTP/2 spec. This
+	// permits using the Framer to test other HTTP/2
+	// implementations' conformance to the spec.
+	// If false, the Write methods will prefer to return an error
+	// rather than comply.
+	AllowIllegalWrites bool
+
+	// AllowIllegalReads permits the Framer's ReadFrame method
+	// to return non-compliant frames or frame orders.
+	// This is for testing and permits using the Framer to test
+	// other HTTP/2 implementations' conformance to the spec.
+	// It is not compatible with ReadMetaHeaders.
+	AllowIllegalReads bool
+
+	// ReadMetaHeaders if non-nil causes ReadFrame to merge
+	// HEADERS and CONTINUATION frames together and return
+	// MetaHeadersFrame instead.
+	ReadMetaHeaders *hpack.Decoder
+
+	// MaxHeaderListSize is the http2 MAX_HEADER_LIST_SIZE.
+	// It's used only if ReadMetaHeaders is set; 0 means a sane default
+	// (currently 16MB)
+	// If the limit is hit, MetaHeadersFrame.Truncated is set true.
+	MaxHeaderListSize uint32
+
+	// TODO: track which type of frame & with which flags was sent
+	// last.  Then return an error (unless AllowIllegalWrites) if
+	// we're in the middle of a header block and a
+	// non-Continuation or Continuation on a different stream is
+	// attempted to be written.
+
+	logReads bool
+
+	debugFramer    *Framer // only use for logging written writes
+	debugFramerBuf *bytes.Buffer
+}
+
+func (fr *Framer) maxHeaderListSize() uint32 {
+	if fr.MaxHeaderListSize == 0 {
+		return 16 << 20 // sane default, per docs
+	}
+	return fr.MaxHeaderListSize
+}
+
+func (f *Framer) startWrite(ftype FrameType, flags Flags, streamID uint32) {
+	// Write the FrameHeader.
+	f.wbuf = append(f.wbuf[:0],
+		0, // 3 bytes of length, filled in in endWrite
+		0,
+		0,
+		byte(ftype),
+		byte(flags),
+		byte(streamID>>24),
+		byte(streamID>>16),
+		byte(streamID>>8),
+		byte(streamID))
+}
+
+func (f *Framer) endWrite() error {
+	// Now that we know the final size, fill in the FrameHeader in
+	// the space previously reserved for it. Abuse append.
+	length := len(f.wbuf) - frameHeaderLen
+	if length >= (1 << 24) {
+		return ErrFrameTooLarge
+	}
+	_ = append(f.wbuf[:0],
+		byte(length>>16),
+		byte(length>>8),
+		byte(length))
+	if logFrameWrites {
+		f.logWrite()
+	}
+
+	n, err := f.w.Write(f.wbuf)
+	if err == nil && n != len(f.wbuf) {
+		err = io.ErrShortWrite
+	}
+	return err
+}
+
+func (f *Framer) logWrite() {
+	if f.debugFramer == nil {
+		f.debugFramerBuf = new(bytes.Buffer)
+		f.debugFramer = NewFramer(nil, f.debugFramerBuf)
+		f.debugFramer.logReads = false // we log it ourselves, saying "wrote" below
+		// Let us read anything, even if we accidentally wrote it
+		// in the wrong order:
+		f.debugFramer.AllowIllegalReads = true
+	}
+	f.debugFramerBuf.Write(f.wbuf)
+	fr, err := f.debugFramer.ReadFrame()
+	if err != nil {
+		log.Printf("http2: Framer %p: failed to decode just-written frame", f)
+		return
+	}
+	log.Printf("http2: Framer %p: wrote %v", f, summarizeFrame(fr))
+}
+
+func (f *Framer) writeByte(v byte)     { f.wbuf = append(f.wbuf, v) }
+func (f *Framer) writeBytes(v []byte)  { f.wbuf = append(f.wbuf, v...) }
+func (f *Framer) writeUint16(v uint16) { f.wbuf = append(f.wbuf, byte(v>>8), byte(v)) }
+func (f *Framer) writeUint32(v uint32) {
+	f.wbuf = append(f.wbuf, byte(v>>24), byte(v>>16), byte(v>>8), byte(v))
+}
+
+const (
+	minMaxFrameSize = 1 << 14
+	maxFrameSize    = 1<<24 - 1
+)
+
+// NewFramer returns a Framer that writes frames to w and reads them from r.
+func NewFramer(w io.Writer, r io.Reader) *Framer {
+	fr := &Framer{
+		w:        w,
+		r:        r,
+		logReads: logFrameReads,
+	}
+	fr.getReadBuf = func(size uint32) []byte {
+		if cap(fr.readBuf) >= int(size) {
+			return fr.readBuf[:size]
+		}
+		fr.readBuf = make([]byte, size)
+		return fr.readBuf
+	}
+	fr.SetMaxReadFrameSize(maxFrameSize)
+	return fr
+}
+
+// SetMaxReadFrameSize sets the maximum size of a frame
+// that will be read by a subsequent call to ReadFrame.
+// It is the caller's responsibility to advertise this
+// limit with a SETTINGS frame.
+func (fr *Framer) SetMaxReadFrameSize(v uint32) {
+	if v > maxFrameSize {
+		v = maxFrameSize
+	}
+	fr.maxReadSize = v
+}
+
+// ErrorDetail returns a more detailed error of the last error
+// returned by Framer.ReadFrame. For instance, if ReadFrame
+// returns a StreamError with code PROTOCOL_ERROR, ErrorDetail
+// will say exactly what was invalid. ErrorDetail is not guaranteed
+// to return a non-nil value and like the rest of the http2 package,
+// its return value is not protected by an API compatibility promise.
+// ErrorDetail is reset after the next call to ReadFrame.
+func (fr *Framer) ErrorDetail() error {
+	return fr.errDetail
+}
+
+// ErrFrameTooLarge is returned from Framer.ReadFrame when the peer
+// sends a frame that is larger than declared with SetMaxReadFrameSize.
+var ErrFrameTooLarge = errors.New("http2: frame too large")
+
+// terminalReadFrameError reports whether err is an unrecoverable
+// error from ReadFrame and no other frames should be read.
+func terminalReadFrameError(err error) bool {
+	if _, ok := err.(StreamError); ok {
+		return false
+	}
+	return err != nil
+}
+
+// ReadFrame reads a single frame. The returned Frame is only valid
+// until the next call to ReadFrame.
+//
+// If the frame is larger than previously set with SetMaxReadFrameSize, the
+// returned error is ErrFrameTooLarge. Other errors may be of type
+// ConnectionError, StreamError, or anything else from from the underlying
+// reader.
+func (fr *Framer) ReadFrame() (Frame, error) {
+	fr.errDetail = nil
+	if fr.lastFrame != nil {
+		fr.lastFrame.invalidate()
+	}
+	fh, err := readFrameHeader(fr.headerBuf[:], fr.r)
+	if err != nil {
+		return nil, err
+	}
+	if fh.Length > fr.maxReadSize {
+		return nil, ErrFrameTooLarge
+	}
+	payload := fr.getReadBuf(fh.Length)
+	if _, err := io.ReadFull(fr.r, payload); err != nil {
+		return nil, err
+	}
+	f, err := typeFrameParser(fh.Type)(fh, payload)
+	if err != nil {
+		if ce, ok := err.(connError); ok {
+			return nil, fr.connError(ce.Code, ce.Reason)
+		}
+		return nil, err
+	}
+	if err := fr.checkFrameOrder(f); err != nil {
+		return nil, err
+	}
+	if fr.logReads {
+		log.Printf("http2: Framer %p: read %v", fr, summarizeFrame(f))
+	}
+	if fh.Type == FrameHeaders && fr.ReadMetaHeaders != nil {
+		return fr.readMetaFrame(f.(*HeadersFrame))
+	}
+	return f, nil
+}
+
+// connError returns ConnectionError(code) but first
+// stashes away a public reason to the caller can optionally relay it
+// to the peer before hanging up on them. This might help others debug
+// their implementations.
+func (fr *Framer) connError(code ErrCode, reason string) error {
+	fr.errDetail = errors.New(reason)
+	return ConnectionError(code)
+}
+
+// checkFrameOrder reports an error if f is an invalid frame to return
+// next from ReadFrame. Mostly it checks whether HEADERS and
+// CONTINUATION frames are contiguous.
+func (fr *Framer) checkFrameOrder(f Frame) error {
+	last := fr.lastFrame
+	fr.lastFrame = f
+	if fr.AllowIllegalReads {
+		return nil
+	}
+
+	fh := f.Header()
+	if fr.lastHeaderStream != 0 {
+		if fh.Type != FrameContinuation {
+			return fr.connError(ErrCodeProtocol,
+				fmt.Sprintf("got %s for stream %d; expected CONTINUATION following %s for stream %d",
+					fh.Type, fh.StreamID,
+					last.Header().Type, fr.lastHeaderStream))
+		}
+		if fh.StreamID != fr.lastHeaderStream {
+			return fr.connError(ErrCodeProtocol,
+				fmt.Sprintf("got CONTINUATION for stream %d; expected stream %d",
+					fh.StreamID, fr.lastHeaderStream))
+		}
+	} else if fh.Type == FrameContinuation {
+		return fr.connError(ErrCodeProtocol, fmt.Sprintf("unexpected CONTINUATION for stream %d", fh.StreamID))
+	}
+
+	switch fh.Type {
+	case FrameHeaders, FrameContinuation:
+		if fh.Flags.Has(FlagHeadersEndHeaders) {
+			fr.lastHeaderStream = 0
+		} else {
+			fr.lastHeaderStream = fh.StreamID
+		}
+	}
+
+	return nil
+}
+
+// A DataFrame conveys arbitrary, variable-length sequences of octets
+// associated with a stream.
+// See http://http2.github.io/http2-spec/#rfc.section.6.1
+type DataFrame struct {
+	FrameHeader
+	data []byte
+}
+
+func (f *DataFrame) StreamEnded() bool {
+	return f.FrameHeader.Flags.Has(FlagDataEndStream)
+}
+
+// Data returns the frame's data octets, not including any padding
+// size byte or padding suffix bytes.
+// The caller must not retain the returned memory past the next
+// call to ReadFrame.
+func (f *DataFrame) Data() []byte {
+	f.checkValid()
+	return f.data
+}
+
+func parseDataFrame(fh FrameHeader, payload []byte) (Frame, error) {
+	if fh.StreamID == 0 {
+		// DATA frames MUST be associated with a stream. If a
+		// DATA frame is received whose stream identifier
+		// field is 0x0, the recipient MUST respond with a
+		// connection error (Section 5.4.1) of type
+		// PROTOCOL_ERROR.
+		return nil, connError{ErrCodeProtocol, "DATA frame with stream ID 0"}
+	}
+	f := &DataFrame{
+		FrameHeader: fh,
+	}
+	var padSize byte
+	if fh.Flags.Has(FlagDataPadded) {
+		var err error
+		payload, padSize, err = readByte(payload)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if int(padSize) > len(payload) {
+		// If the length of the padding is greater than the
+		// length of the frame payload, the recipient MUST
+		// treat this as a connection error.
+		// Filed: https://github.com/http2/http2-spec/issues/610
+		return nil, connError{ErrCodeProtocol, "pad size larger than data payload"}
+	}
+	f.data = payload[:len(payload)-int(padSize)]
+	return f, nil
+}
+
+var (
+	errStreamID    = errors.New("invalid stream ID")
+	errDepStreamID = errors.New("invalid dependent stream ID")
+)
+
+func validStreamIDOrZero(streamID uint32) bool {
+	return streamID&(1<<31) == 0
+}
+
+func validStreamID(streamID uint32) bool {
+	return streamID != 0 && streamID&(1<<31) == 0
+}
+
+// WriteData writes a DATA frame.
+//
+// It will perform exactly one Write to the underlying Writer.
+// It is the caller's responsibility to not call other Write methods concurrently.
+func (f *Framer) WriteData(streamID uint32, endStream bool, data []byte) error {
+	// TODO: ignoring padding for now. will add when somebody cares.
+	if !validStreamID(streamID) && !f.AllowIllegalWrites {
+		return errStreamID
+	}
+	var flags Flags
+	if endStream {
+		flags |= FlagDataEndStream
+	}
+	f.startWrite(FrameData, flags, streamID)
+	f.wbuf = append(f.wbuf, data...)
+	return f.endWrite()
+}
+
+// A SettingsFrame conveys configuration parameters that affect how
+// endpoints communicate, such as preferences and constraints on peer
+// behavior.
+//
+// See http://http2.github.io/http2-spec/#SETTINGS
+type SettingsFrame struct {
+	FrameHeader
+	p []byte
+}
+
+func parseSettingsFrame(fh FrameHeader, p []byte) (Frame, error) {
+	if fh.Flags.Has(FlagSettingsAck) && fh.Length > 0 {
+		// When this (ACK 0x1) bit is set, the payload of the
+		// SETTINGS frame MUST be empty.  Receipt of a
+		// SETTINGS frame with the ACK flag set and a length
+		// field value other than 0 MUST be treated as a
+		// connection error (Section 5.4.1) of type
+		// FRAME_SIZE_ERROR.
+		return nil, ConnectionError(ErrCodeFrameSize)
+	}
+	if fh.StreamID != 0 {
+		// SETTINGS frames always apply to a connection,
+		// never a single stream.  The stream identifier for a
+		// SETTINGS frame MUST be zero (0x0).  If an endpoint
+		// receives a SETTINGS frame whose stream identifier
+		// field is anything other than 0x0, the endpoint MUST
+		// respond with a connection error (Section 5.4.1) of
+		// type PROTOCOL_ERROR.
+		return nil, ConnectionError(ErrCodeProtocol)
+	}
+	if len(p)%6 != 0 {
+		// Expecting even number of 6 byte settings.
+		return nil, ConnectionError(ErrCodeFrameSize)
+	}
+	f := &SettingsFrame{FrameHeader: fh, p: p}
+	if v, ok := f.Value(SettingInitialWindowSize); ok && v > (1<<31)-1 {
+		// Values above the maximum flow control window size of 2^31 - 1 MUST
+		// be treated as a connection error (Section 5.4.1) of type
+		// FLOW_CONTROL_ERROR.
+		return nil, ConnectionError(ErrCodeFlowControl)
+	}
+	return f, nil
+}
+
+func (f *SettingsFrame) IsAck() bool {
+	return f.FrameHeader.Flags.Has(FlagSettingsAck)
+}
+
+func (f *SettingsFrame) Value(s SettingID) (v uint32, ok bool) {
+	f.checkValid()
+	buf := f.p
+	for len(buf) > 0 {
+		settingID := SettingID(binary.BigEndian.Uint16(buf[:2]))
+		if settingID == s {
+			return binary.BigEndian.Uint32(buf[2:6]), true
+		}
+		buf = buf[6:]
+	}
+	return 0, false
+}
+
+// ForeachSetting runs fn for each setting.
+// It stops and returns the first error.
+func (f *SettingsFrame) ForeachSetting(fn func(Setting) error) error {
+	f.checkValid()
+	buf := f.p
+	for len(buf) > 0 {
+		if err := fn(Setting{
+			SettingID(binary.BigEndian.Uint16(buf[:2])),
+			binary.BigEndian.Uint32(buf[2:6]),
+		}); err != nil {
+			return err
+		}
+		buf = buf[6:]
+	}
+	return nil
+}
+
+// WriteSettings writes a SETTINGS frame with zero or more settings
+// specified and the ACK bit not set.
+//
+// It will perform exactly one Write to the underlying Writer.
+// It is the caller's responsibility to not call other Write methods concurrently.
+func (f *Framer) WriteSettings(settings ...Setting) error {
+	f.startWrite(FrameSettings, 0, 0)
+	for _, s := range settings {
+		f.writeUint16(uint16(s.ID))
+		f.writeUint32(s.Val)
+	}
+	return f.endWrite()
+}
+
+// WriteSettings writes an empty SETTINGS frame with the ACK bit set.
+//
+// It will perform exactly one Write to the underlying Writer.
+// It is the caller's responsibility to not call other Write methods concurrently.
+func (f *Framer) WriteSettingsAck() error {
+	f.startWrite(FrameSettings, FlagSettingsAck, 0)
+	return f.endWrite()
+}
+
+// A PingFrame is a mechanism for measuring a minimal round trip time
+// from the sender, as well as determining whether an idle connection
+// is still functional.
+// See http://http2.github.io/http2-spec/#rfc.section.6.7
+type PingFrame struct {
+	FrameHeader
+	Data [8]byte
+}
+
+func (f *PingFrame) IsAck() bool { return f.Flags.Has(FlagPingAck) }
+
+func parsePingFrame(fh FrameHeader, payload []byte) (Frame, error) {
+	if len(payload) != 8 {
+		return nil, ConnectionError(ErrCodeFrameSize)
+	}
+	if fh.StreamID != 0 {
+		return nil, ConnectionError(ErrCodeProtocol)
+	}
+	f := &PingFrame{FrameHeader: fh}
+	copy(f.Data[:], payload)
+	return f, nil
+}
+
+func (f *Framer) WritePing(ack bool, data [8]byte) error {
+	var flags Flags
+	if ack {
+		flags = FlagPingAck
+	}
+	f.startWrite(FramePing, flags, 0)
+	f.writeBytes(data[:])
+	return f.endWrite()
+}
+
+// A GoAwayFrame informs the remote peer to stop creating streams on this connection.
+// See http://http2.github.io/http2-spec/#rfc.section.6.8
+type GoAwayFrame struct {
+	FrameHeader
+	LastStreamID uint32
+	ErrCode      ErrCode
+	debugData    []byte
+}
+
+// DebugData returns any debug data in the GOAWAY frame. Its contents
+// are not defined.
+// The caller must not retain the returned memory past the next
+// call to ReadFrame.
+func (f *GoAwayFrame) DebugData() []byte {
+	f.checkValid()
+	return f.debugData
+}
+
+func parseGoAwayFrame(fh FrameHeader, p []byte) (Frame, error) {
+	if fh.StreamID != 0 {
+		return nil, ConnectionError(ErrCodeProtocol)
+	}
+	if len(p) < 8 {
+		return nil, ConnectionError(ErrCodeFrameSize)
+	}
+	return &GoAwayFrame{
+		FrameHeader:  fh,
+		LastStreamID: binary.BigEndian.Uint32(p[:4]) & (1<<31 - 1),
+		ErrCode:      ErrCode(binary.BigEndian.Uint32(p[4:8])),
+		debugData:    p[8:],
+	}, nil
+}
+
+func (f *Framer) WriteGoAway(maxStreamID uint32, code ErrCode, debugData []byte) error {
+	f.startWrite(FrameGoAway, 0, 0)
+	f.writeUint32(maxStreamID & (1<<31 - 1))
+	f.writeUint32(uint32(code))
+	f.writeBytes(debugData)
+	return f.endWrite()
+}
+
+// An UnknownFrame is the frame type returned when the frame type is unknown
+// or no specific frame type parser exists.
+type UnknownFrame struct {
+	FrameHeader
+	p []byte
+}
+
+// Payload returns the frame's payload (after the header).  It is not
+// valid to call this method after a subsequent call to
+// Framer.ReadFrame, nor is it valid to retain the returned slice.
+// The memory is owned by the Framer and is invalidated when the next
+// frame is read.
+func (f *UnknownFrame) Payload() []byte {
+	f.checkValid()
+	return f.p
+}
+
+func parseUnknownFrame(fh FrameHeader, p []byte) (Frame, error) {
+	return &UnknownFrame{fh, p}, nil
+}
+
+// A WindowUpdateFrame is used to implement flow control.
+// See http://http2.github.io/http2-spec/#rfc.section.6.9
+type WindowUpdateFrame struct {
+	FrameHeader
+	Increment uint32 // never read with high bit set
+}
+
+func parseWindowUpdateFrame(fh FrameHeader, p []byte) (Frame, error) {
+	if len(p) != 4 {
+		return nil, ConnectionError(ErrCodeFrameSize)
+	}
+	inc := binary.BigEndian.Uint32(p[:4]) & 0x7fffffff // mask off high reserved bit
+	if inc == 0 {
+		// A receiver MUST treat the receipt of a
+		// WINDOW_UPDATE frame with an flow control window
+		// increment of 0 as a stream error (Section 5.4.2) of
+		// type PROTOCOL_ERROR; errors on the connection flow
+		// control window MUST be treated as a connection
+		// error (Section 5.4.1).
+		if fh.StreamID == 0 {
+			return nil, ConnectionError(ErrCodeProtocol)
+		}
+		return nil, StreamError{fh.StreamID, ErrCodeProtocol}
+	}
+	return &WindowUpdateFrame{
+		FrameHeader: fh,
+		Increment:   inc,
+	}, nil
+}
+
+// WriteWindowUpdate writes a WINDOW_UPDATE frame.
+// The increment value must be between 1 and 2,147,483,647, inclusive.
+// If the Stream ID is zero, the window update applies to the
+// connection as a whole.
+func (f *Framer) WriteWindowUpdate(streamID, incr uint32) error {
+	// "The legal range for the increment to the flow control window is 1 to 2^31-1 (2,147,483,647) octets."
+	if (incr < 1 || incr > 2147483647) && !f.AllowIllegalWrites {
+		return errors.New("illegal window increment value")
+	}
+	f.startWrite(FrameWindowUpdate, 0, streamID)
+	f.writeUint32(incr)
+	return f.endWrite()
+}
+
+// A HeadersFrame is used to open a stream and additionally carries a
+// header block fragment.
+type HeadersFrame struct {
+	FrameHeader
+
+	// Priority is set if FlagHeadersPriority is set in the FrameHeader.
+	Priority PriorityParam
+
+	headerFragBuf []byte // not owned
+}
+
+func (f *HeadersFrame) HeaderBlockFragment() []byte {
+	f.checkValid()
+	return f.headerFragBuf
+}
+
+func (f *HeadersFrame) HeadersEnded() bool {
+	return f.FrameHeader.Flags.Has(FlagHeadersEndHeaders)
+}
+
+func (f *HeadersFrame) StreamEnded() bool {
+	return f.FrameHeader.Flags.Has(FlagHeadersEndStream)
+}
+
+func (f *HeadersFrame) HasPriority() bool {
+	return f.FrameHeader.Flags.Has(FlagHeadersPriority)
+}
+
+func parseHeadersFrame(fh FrameHeader, p []byte) (_ Frame, err error) {
+	hf := &HeadersFrame{
+		FrameHeader: fh,
+	}
+	if fh.StreamID == 0 {
+		// HEADERS frames MUST be associated with a stream.  If a HEADERS frame
+		// is received whose stream identifier field is 0x0, the recipient MUST
+		// respond with a connection error (Section 5.4.1) of type
+		// PROTOCOL_ERROR.
+		return nil, connError{ErrCodeProtocol, "HEADERS frame with stream ID 0"}
+	}
+	var padLength uint8
+	if fh.Flags.Has(FlagHeadersPadded) {
+		if p, padLength, err = readByte(p); err != nil {
+			return
+		}
+	}
+	if fh.Flags.Has(FlagHeadersPriority) {
+		var v uint32
+		p, v, err = readUint32(p)
+		if err != nil {
+			return nil, err
+		}
+		hf.Priority.StreamDep = v & 0x7fffffff
+		hf.Priority.Exclusive = (v != hf.Priority.StreamDep) // high bit was set
+		p, hf.Priority.Weight, err = readByte(p)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if len(p)-int(padLength) <= 0 {
+		return nil, StreamError{fh.StreamID, ErrCodeProtocol}
+	}
+	hf.headerFragBuf = p[:len(p)-int(padLength)]
+	return hf, nil
+}
+
+// HeadersFrameParam are the parameters for writing a HEADERS frame.
+type HeadersFrameParam struct {
+	// StreamID is the required Stream ID to initiate.
+	StreamID uint32
+	// BlockFragment is part (or all) of a Header Block.
+	BlockFragment []byte
+
+	// EndStream indicates that the header block is the last that
+	// the endpoint will send for the identified stream. Setting
+	// this flag causes the stream to enter one of "half closed"
+	// states.
+	EndStream bool
+
+	// EndHeaders indicates that this frame contains an entire
+	// header block and is not followed by any
+	// CONTINUATION frames.
+	EndHeaders bool
+
+	// PadLength is the optional number of bytes of zeros to add
+	// to this frame.
+	PadLength uint8
+
+	// Priority, if non-zero, includes stream priority information
+	// in the HEADER frame.
+	Priority PriorityParam
+}
+
+// WriteHeaders writes a single HEADERS frame.
+//
+// This is a low-level header writing method. Encoding headers and
+// splitting them into any necessary CONTINUATION frames is handled
+// elsewhere.
+//
+// It will perform exactly one Write to the underlying Writer.
+// It is the caller's responsibility to not call other Write methods concurrently.
+func (f *Framer) WriteHeaders(p HeadersFrameParam) error {
+	if !validStreamID(p.StreamID) && !f.AllowIllegalWrites {
+		return errStreamID
+	}
+	var flags Flags
+	if p.PadLength != 0 {
+		flags |= FlagHeadersPadded
+	}
+	if p.EndStream {
+		flags |= FlagHeadersEndStream
+	}
+	if p.EndHeaders {
+		flags |= FlagHeadersEndHeaders
+	}
+	if !p.Priority.IsZero() {
+		flags |= FlagHeadersPriority
+	}
+	f.startWrite(FrameHeaders, flags, p.StreamID)
+	if p.PadLength != 0 {
+		f.writeByte(p.PadLength)
+	}
+	if !p.Priority.IsZero() {
+		v := p.Priority.StreamDep
+		if !validStreamIDOrZero(v) && !f.AllowIllegalWrites {
+			return errDepStreamID
+		}
+		if p.Priority.Exclusive {
+			v |= 1 << 31
+		}
+		f.writeUint32(v)
+		f.writeByte(p.Priority.Weight)
+	}
+	f.wbuf = append(f.wbuf, p.BlockFragment...)
+	f.wbuf = append(f.wbuf, padZeros[:p.PadLength]...)
+	return f.endWrite()
+}
+
+// A PriorityFrame specifies the sender-advised priority of a stream.
+// See http://http2.github.io/http2-spec/#rfc.section.6.3
+type PriorityFrame struct {
+	FrameHeader
+	PriorityParam
+}
+
+// PriorityParam are the stream prioritzation parameters.
+type PriorityParam struct {
+	// StreamDep is a 31-bit stream identifier for the
+	// stream that this stream depends on. Zero means no
+	// dependency.
+	StreamDep uint32
+
+	// Exclusive is whether the dependency is exclusive.
+	Exclusive bool
+
+	// Weight is the stream's zero-indexed weight. It should be
+	// set together with StreamDep, or neither should be set.  Per
+	// the spec, "Add one to the value to obtain a weight between
+	// 1 and 256."
+	Weight uint8
+}
+
+func (p PriorityParam) IsZero() bool {
+	return p == PriorityParam{}
+}
+
+func parsePriorityFrame(fh FrameHeader, payload []byte) (Frame, error) {
+	if fh.StreamID == 0 {
+		return nil, connError{ErrCodeProtocol, "PRIORITY frame with stream ID 0"}
+	}
+	if len(payload) != 5 {
+		return nil, connError{ErrCodeFrameSize, fmt.Sprintf("PRIORITY frame payload size was %d; want 5", len(payload))}
+	}
+	v := binary.BigEndian.Uint32(payload[:4])
+	streamID := v & 0x7fffffff // mask off high bit
+	return &PriorityFrame{
+		FrameHeader: fh,
+		PriorityParam: PriorityParam{
+			Weight:    payload[4],
+			StreamDep: streamID,
+			Exclusive: streamID != v, // was high bit set?
+		},
+	}, nil
+}
+
+// WritePriority writes a PRIORITY frame.
+//
+// It will perform exactly one Write to the underlying Writer.
+// It is the caller's responsibility to not call other Write methods concurrently.
+func (f *Framer) WritePriority(streamID uint32, p PriorityParam) error {
+	if !validStreamID(streamID) && !f.AllowIllegalWrites {
+		return errStreamID
+	}
+	if !validStreamIDOrZero(p.StreamDep) {
+		return errDepStreamID
+	}
+	f.startWrite(FramePriority, 0, streamID)
+	v := p.StreamDep
+	if p.Exclusive {
+		v |= 1 << 31
+	}
+	f.writeUint32(v)
+	f.writeByte(p.Weight)
+	return f.endWrite()
+}
+
+// A RSTStreamFrame allows for abnormal termination of a stream.
+// See http://http2.github.io/http2-spec/#rfc.section.6.4
+type RSTStreamFrame struct {
+	FrameHeader
+	ErrCode ErrCode
+}
+
+func parseRSTStreamFrame(fh FrameHeader, p []byte) (Frame, error) {
+	if len(p) != 4 {
+		return nil, ConnectionError(ErrCodeFrameSize)
+	}
+	if fh.StreamID == 0 {
+		return nil, ConnectionError(ErrCodeProtocol)
+	}
+	return &RSTStreamFrame{fh, ErrCode(binary.BigEndian.Uint32(p[:4]))}, nil
+}
+
+// WriteRSTStream writes a RST_STREAM frame.
+//
+// It will perform exactly one Write to the underlying Writer.
+// It is the caller's responsibility to not call other Write methods concurrently.
+func (f *Framer) WriteRSTStream(streamID uint32, code ErrCode) error {
+	if !validStreamID(streamID) && !f.AllowIllegalWrites {
+		return errStreamID
+	}
+	f.startWrite(FrameRSTStream, 0, streamID)
+	f.writeUint32(uint32(code))
+	return f.endWrite()
+}
+
+// A ContinuationFrame is used to continue a sequence of header block fragments.
+// See http://http2.github.io/http2-spec/#rfc.section.6.10
+type ContinuationFrame struct {
+	FrameHeader
+	headerFragBuf []byte
+}
+
+func parseContinuationFrame(fh FrameHeader, p []byte) (Frame, error) {
+	if fh.StreamID == 0 {
+		return nil, connError{ErrCodeProtocol, "CONTINUATION frame with stream ID 0"}
+	}
+	return &ContinuationFrame{fh, p}, nil
+}
+
+func (f *ContinuationFrame) HeaderBlockFragment() []byte {
+	f.checkValid()
+	return f.headerFragBuf
+}
+
+func (f *ContinuationFrame) HeadersEnded() bool {
+	return f.FrameHeader.Flags.Has(FlagContinuationEndHeaders)
+}
+
+// WriteContinuation writes a CONTINUATION frame.
+//
+// It will perform exactly one Write to the underlying Writer.
+// It is the caller's responsibility to not call other Write methods concurrently.
+func (f *Framer) WriteContinuation(streamID uint32, endHeaders bool, headerBlockFragment []byte) error {
+	if !validStreamID(streamID) && !f.AllowIllegalWrites {
+		return errStreamID
+	}
+	var flags Flags
+	if endHeaders {
+		flags |= FlagContinuationEndHeaders
+	}
+	f.startWrite(FrameContinuation, flags, streamID)
+	f.wbuf = append(f.wbuf, headerBlockFragment...)
+	return f.endWrite()
+}
+
+// A PushPromiseFrame is used to initiate a server stream.
+// See http://http2.github.io/http2-spec/#rfc.section.6.6
+type PushPromiseFrame struct {
+	FrameHeader
+	PromiseID     uint32
+	headerFragBuf []byte // not owned
+}
+
+func (f *PushPromiseFrame) HeaderBlockFragment() []byte {
+	f.checkValid()
+	return f.headerFragBuf
+}
+
+func (f *PushPromiseFrame) HeadersEnded() bool {
+	return f.FrameHeader.Flags.Has(FlagPushPromiseEndHeaders)
+}
+
+func parsePushPromise(fh FrameHeader, p []byte) (_ Frame, err error) {
+	pp := &PushPromiseFrame{
+		FrameHeader: fh,
+	}
+	if pp.StreamID == 0 {
+		// PUSH_PROMISE frames MUST be associated with an existing,
+		// peer-initiated stream. The stream identifier of a
+		// PUSH_PROMISE frame indicates the stream it is associated
+		// with. If the stream identifier field specifies the value
+		// 0x0, a recipient MUST respond with a connection error
+		// (Section 5.4.1) of type PROTOCOL_ERROR.
+		return nil, ConnectionError(ErrCodeProtocol)
+	}
+	// The PUSH_PROMISE frame includes optional padding.
+	// Padding fields and flags are identical to those defined for DATA frames
+	var padLength uint8
+	if fh.Flags.Has(FlagPushPromisePadded) {
+		if p, padLength, err = readByte(p); err != nil {
+			return
+		}
+	}
+
+	p, pp.PromiseID, err = readUint32(p)
+	if err != nil {
+		return
+	}
+	pp.PromiseID = pp.PromiseID & (1<<31 - 1)
+
+	if int(padLength) > len(p) {
+		// like the DATA frame, error out if padding is longer than the body.
+		return nil, ConnectionError(ErrCodeProtocol)
+	}
+	pp.headerFragBuf = p[:len(p)-int(padLength)]
+	return pp, nil
+}
+
+// PushPromiseParam are the parameters for writing a PUSH_PROMISE frame.
+type PushPromiseParam struct {
+	// StreamID is the required Stream ID to initiate.
+	StreamID uint32
+
+	// PromiseID is the required Stream ID which this
+	// Push Promises
+	PromiseID uint32
+
+	// BlockFragment is part (or all) of a Header Block.
+	BlockFragment []byte
+
+	// EndHeaders indicates that this frame contains an entire
+	// header block and is not followed by any
+	// CONTINUATION frames.
+	EndHeaders bool
+
+	// PadLength is the optional number of bytes of zeros to add
+	// to this frame.
+	PadLength uint8
+}
+
+// WritePushPromise writes a single PushPromise Frame.
+//
+// As with Header Frames, This is the low level call for writing
+// individual frames. Continuation frames are handled elsewhere.
+//
+// It will perform exactly one Write to the underlying Writer.
+// It is the caller's responsibility to not call other Write methods concurrently.
+func (f *Framer) WritePushPromise(p PushPromiseParam) error {
+	if !validStreamID(p.StreamID) && !f.AllowIllegalWrites {
+		return errStreamID
+	}
+	var flags Flags
+	if p.PadLength != 0 {
+		flags |= FlagPushPromisePadded
+	}
+	if p.EndHeaders {
+		flags |= FlagPushPromiseEndHeaders
+	}
+	f.startWrite(FramePushPromise, flags, p.StreamID)
+	if p.PadLength != 0 {
+		f.writeByte(p.PadLength)
+	}
+	if !validStreamID(p.PromiseID) && !f.AllowIllegalWrites {
+		return errStreamID
+	}
+	f.writeUint32(p.PromiseID)
+	f.wbuf = append(f.wbuf, p.BlockFragment...)
+	f.wbuf = append(f.wbuf, padZeros[:p.PadLength]...)
+	return f.endWrite()
+}
+
+// WriteRawFrame writes a raw frame. This can be used to write
+// extension frames unknown to this package.
+func (f *Framer) WriteRawFrame(t FrameType, flags Flags, streamID uint32, payload []byte) error {
+	f.startWrite(t, flags, streamID)
+	f.writeBytes(payload)
+	return f.endWrite()
+}
+
+func readByte(p []byte) (remain []byte, b byte, err error) {
+	if len(p) == 0 {
+		return nil, 0, io.ErrUnexpectedEOF
+	}
+	return p[1:], p[0], nil
+}
+
+func readUint32(p []byte) (remain []byte, v uint32, err error) {
+	if len(p) < 4 {
+		return nil, 0, io.ErrUnexpectedEOF
+	}
+	return p[4:], binary.BigEndian.Uint32(p[:4]), nil
+}
+
+type streamEnder interface {
+	StreamEnded() bool
+}
+
+type headersEnder interface {
+	HeadersEnded() bool
+}
+
+type headersOrContinuation interface {
+	headersEnder
+	HeaderBlockFragment() []byte
+}
+
+// A MetaHeadersFrame is the representation of one HEADERS frame and
+// zero or more contiguous CONTINUATION frames and the decoding of
+// their HPACK-encoded contents.
+//
+// This type of frame does not appear on the wire and is only returned
+// by the Framer when Framer.ReadMetaHeaders is set.
+type MetaHeadersFrame struct {
+	*HeadersFrame
+
+	// Fields are the fields contained in the HEADERS and
+	// CONTINUATION frames. The underlying slice is owned by the
+	// Framer and must not be retained after the next call to
+	// ReadFrame.
+	//
+	// Fields are guaranteed to be in the correct http2 order and
+	// not have unknown pseudo header fields or invalid header
+	// field names or values. Required pseudo header fields may be
+	// missing, however. Use the MetaHeadersFrame.Pseudo accessor
+	// method access pseudo headers.
+	Fields []hpack.HeaderField
+
+	// Truncated is whether the max header list size limit was hit
+	// and Fields is incomplete. The hpack decoder state is still
+	// valid, however.
+	Truncated bool
+}
+
+// PseudoValue returns the given pseudo header field's value.
+// The provided pseudo field should not contain the leading colon.
+func (mh *MetaHeadersFrame) PseudoValue(pseudo string) string {
+	for _, hf := range mh.Fields {
+		if !hf.IsPseudo() {
+			return ""
+		}
+		if hf.Name[1:] == pseudo {
+			return hf.Value
+		}
+	}
+	return ""
+}
+
+// RegularFields returns the regular (non-pseudo) header fields of mh.
+// The caller does not own the returned slice.
+func (mh *MetaHeadersFrame) RegularFields() []hpack.HeaderField {
+	for i, hf := range mh.Fields {
+		if !hf.IsPseudo() {
+			return mh.Fields[i:]
+		}
+	}
+	return nil
+}
+
+// PseudoFields returns the pseudo header fields of mh.
+// The caller does not own the returned slice.
+func (mh *MetaHeadersFrame) PseudoFields() []hpack.HeaderField {
+	for i, hf := range mh.Fields {
+		if !hf.IsPseudo() {
+			return mh.Fields[:i]
+		}
+	}
+	return mh.Fields
+}
+
+func (mh *MetaHeadersFrame) checkPseudos() error {
+	var isRequest, isResponse bool
+	pf := mh.PseudoFields()
+	for i, hf := range pf {
+		switch hf.Name {
+		case ":method", ":path", ":scheme", ":authority":
+			isRequest = true
+		case ":status":
+			isResponse = true
+		default:
+			return pseudoHeaderError(hf.Name)
+		}
+		// Check for duplicates.
+		// This would be a bad algorithm, but N is 4.
+		// And this doesn't allocate.
+		for _, hf2 := range pf[:i] {
+			if hf.Name == hf2.Name {
+				return duplicatePseudoHeaderError(hf.Name)
+			}
+		}
+	}
+	if isRequest && isResponse {
+		return errMixPseudoHeaderTypes
+	}
+	return nil
+}
+
+func (fr *Framer) maxHeaderStringLen() int {
+	v := fr.maxHeaderListSize()
+	if uint32(int(v)) == v {
+		return int(v)
+	}
+	// They had a crazy big number for MaxHeaderBytes anyway,
+	// so give them unlimited header lengths:
+	return 0
+}
+
+// readMetaFrame returns 0 or more CONTINUATION frames from fr and
+// merge them into into the provided hf and returns a MetaHeadersFrame
+// with the decoded hpack values.
+func (fr *Framer) readMetaFrame(hf *HeadersFrame) (*MetaHeadersFrame, error) {
+	if fr.AllowIllegalReads {
+		return nil, errors.New("illegal use of AllowIllegalReads with ReadMetaHeaders")
+	}
+	mh := &MetaHeadersFrame{
+		HeadersFrame: hf,
+	}
+	var remainSize = fr.maxHeaderListSize()
+	var sawRegular bool
+
+	var invalid error // pseudo header field errors
+	hdec := fr.ReadMetaHeaders
+	hdec.SetEmitEnabled(true)
+	hdec.SetMaxStringLength(fr.maxHeaderStringLen())
+	hdec.SetEmitFunc(func(hf hpack.HeaderField) {
+		if !httplex.ValidHeaderFieldValue(hf.Value) {
+			invalid = headerFieldValueError(hf.Value)
+		}
+		isPseudo := strings.HasPrefix(hf.Name, ":")
+		if isPseudo {
+			if sawRegular {
+				invalid = errPseudoAfterRegular
+			}
+		} else {
+			sawRegular = true
+			if !validWireHeaderFieldName(hf.Name) {
+				invalid = headerFieldNameError(hf.Name)
+			}
+		}
+
+		if invalid != nil {
+			hdec.SetEmitEnabled(false)
+			return
+		}
+
+		size := hf.Size()
+		if size > remainSize {
+			hdec.SetEmitEnabled(false)
+			mh.Truncated = true
+			return
+		}
+		remainSize -= size
+
+		mh.Fields = append(mh.Fields, hf)
+	})
+	// Lose reference to MetaHeadersFrame:
+	defer hdec.SetEmitFunc(func(hf hpack.HeaderField) {})
+
+	var hc headersOrContinuation = hf
+	for {
+		frag := hc.HeaderBlockFragment()
+		if _, err := hdec.Write(frag); err != nil {
+			return nil, ConnectionError(ErrCodeCompression)
+		}
+
+		if hc.HeadersEnded() {
+			break
+		}
+		if f, err := fr.ReadFrame(); err != nil {
+			return nil, err
+		} else {
+			hc = f.(*ContinuationFrame) // guaranteed by checkFrameOrder
+		}
+	}
+
+	mh.HeadersFrame.headerFragBuf = nil
+	mh.HeadersFrame.invalidate()
+
+	if err := hdec.Close(); err != nil {
+		return nil, ConnectionError(ErrCodeCompression)
+	}
+	if invalid != nil {
+		fr.errDetail = invalid
+		return nil, StreamError{mh.StreamID, ErrCodeProtocol}
+	}
+	if err := mh.checkPseudos(); err != nil {
+		fr.errDetail = err
+		return nil, StreamError{mh.StreamID, ErrCodeProtocol}
+	}
+	return mh, nil
+}
+
+func summarizeFrame(f Frame) string {
+	var buf bytes.Buffer
+	f.Header().writeDebug(&buf)
+	switch f := f.(type) {
+	case *SettingsFrame:
+		n := 0
+		f.ForeachSetting(func(s Setting) error {
+			n++
+			if n == 1 {
+				buf.WriteString(", settings:")
+			}
+			fmt.Fprintf(&buf, " %v=%v,", s.ID, s.Val)
+			return nil
+		})
+		if n > 0 {
+			buf.Truncate(buf.Len() - 1) // remove trailing comma
+		}
+	case *DataFrame:
+		data := f.Data()
+		const max = 256
+		if len(data) > max {
+			data = data[:max]
+		}
+		fmt.Fprintf(&buf, " data=%q", data)
+		if len(f.Data()) > max {
+			fmt.Fprintf(&buf, " (%d bytes omitted)", len(f.Data())-max)
+		}
+	case *WindowUpdateFrame:
+		if f.StreamID == 0 {
+			buf.WriteString(" (conn)")
+		}
+		fmt.Fprintf(&buf, " incr=%v", f.Increment)
+	case *PingFrame:
+		fmt.Fprintf(&buf, " ping=%q", f.Data[:])
+	case *GoAwayFrame:
+		fmt.Fprintf(&buf, " LastStreamID=%v ErrCode=%v Debug=%q",
+			f.LastStreamID, f.ErrCode, f.debugData)
+	case *RSTStreamFrame:
+		fmt.Fprintf(&buf, " ErrCode=%v", f.ErrCode)
+	}
+	return buf.String()
+}
diff --git a/vendor/golang.org/x/net/http2/go16.go b/vendor/golang.org/x/net/http2/go16.go
new file mode 100644
index 0000000..00b2e9e
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/go16.go
@@ -0,0 +1,16 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.6
+
+package http2
+
+import (
+	"net/http"
+	"time"
+)
+
+func transportExpectContinueTimeout(t1 *http.Transport) time.Duration {
+	return t1.ExpectContinueTimeout
+}
diff --git a/vendor/golang.org/x/net/http2/go17.go b/vendor/golang.org/x/net/http2/go17.go
new file mode 100644
index 0000000..730319d
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/go17.go
@@ -0,0 +1,94 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.7
+
+package http2
+
+import (
+	"context"
+	"net"
+	"net/http"
+	"net/http/httptrace"
+	"time"
+)
+
+type contextContext interface {
+	context.Context
+}
+
+func serverConnBaseContext(c net.Conn, opts *ServeConnOpts) (ctx contextContext, cancel func()) {
+	ctx, cancel = context.WithCancel(context.Background())
+	ctx = context.WithValue(ctx, http.LocalAddrContextKey, c.LocalAddr())
+	if hs := opts.baseConfig(); hs != nil {
+		ctx = context.WithValue(ctx, http.ServerContextKey, hs)
+	}
+	return
+}
+
+func contextWithCancel(ctx contextContext) (_ contextContext, cancel func()) {
+	return context.WithCancel(ctx)
+}
+
+func requestWithContext(req *http.Request, ctx contextContext) *http.Request {
+	return req.WithContext(ctx)
+}
+
+type clientTrace httptrace.ClientTrace
+
+func reqContext(r *http.Request) context.Context { return r.Context() }
+
+func setResponseUncompressed(res *http.Response) { res.Uncompressed = true }
+
+func traceGotConn(req *http.Request, cc *ClientConn) {
+	trace := httptrace.ContextClientTrace(req.Context())
+	if trace == nil || trace.GotConn == nil {
+		return
+	}
+	ci := httptrace.GotConnInfo{Conn: cc.tconn}
+	cc.mu.Lock()
+	ci.Reused = cc.nextStreamID > 1
+	ci.WasIdle = len(cc.streams) == 0 && ci.Reused
+	if ci.WasIdle && !cc.lastActive.IsZero() {
+		ci.IdleTime = time.Now().Sub(cc.lastActive)
+	}
+	cc.mu.Unlock()
+
+	trace.GotConn(ci)
+}
+
+func traceWroteHeaders(trace *clientTrace) {
+	if trace != nil && trace.WroteHeaders != nil {
+		trace.WroteHeaders()
+	}
+}
+
+func traceGot100Continue(trace *clientTrace) {
+	if trace != nil && trace.Got100Continue != nil {
+		trace.Got100Continue()
+	}
+}
+
+func traceWait100Continue(trace *clientTrace) {
+	if trace != nil && trace.Wait100Continue != nil {
+		trace.Wait100Continue()
+	}
+}
+
+func traceWroteRequest(trace *clientTrace, err error) {
+	if trace != nil && trace.WroteRequest != nil {
+		trace.WroteRequest(httptrace.WroteRequestInfo{Err: err})
+	}
+}
+
+func traceFirstResponseByte(trace *clientTrace) {
+	if trace != nil && trace.GotFirstResponseByte != nil {
+		trace.GotFirstResponseByte()
+	}
+}
+
+func requestTrace(req *http.Request) *clientTrace {
+	trace := httptrace.ContextClientTrace(req.Context())
+	return (*clientTrace)(trace)
+}
diff --git a/vendor/golang.org/x/net/http2/gotrack.go b/vendor/golang.org/x/net/http2/gotrack.go
new file mode 100644
index 0000000..9933c9f
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/gotrack.go
@@ -0,0 +1,170 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Defensive debug-only utility to track that functions run on the
+// goroutine that they're supposed to.
+
+package http2
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+	"runtime"
+	"strconv"
+	"sync"
+)
+
+var DebugGoroutines = os.Getenv("DEBUG_HTTP2_GOROUTINES") == "1"
+
+type goroutineLock uint64
+
+func newGoroutineLock() goroutineLock {
+	if !DebugGoroutines {
+		return 0
+	}
+	return goroutineLock(curGoroutineID())
+}
+
+func (g goroutineLock) check() {
+	if !DebugGoroutines {
+		return
+	}
+	if curGoroutineID() != uint64(g) {
+		panic("running on the wrong goroutine")
+	}
+}
+
+func (g goroutineLock) checkNotOn() {
+	if !DebugGoroutines {
+		return
+	}
+	if curGoroutineID() == uint64(g) {
+		panic("running on the wrong goroutine")
+	}
+}
+
+var goroutineSpace = []byte("goroutine ")
+
+func curGoroutineID() uint64 {
+	bp := littleBuf.Get().(*[]byte)
+	defer littleBuf.Put(bp)
+	b := *bp
+	b = b[:runtime.Stack(b, false)]
+	// Parse the 4707 out of "goroutine 4707 ["
+	b = bytes.TrimPrefix(b, goroutineSpace)
+	i := bytes.IndexByte(b, ' ')
+	if i < 0 {
+		panic(fmt.Sprintf("No space found in %q", b))
+	}
+	b = b[:i]
+	n, err := parseUintBytes(b, 10, 64)
+	if err != nil {
+		panic(fmt.Sprintf("Failed to parse goroutine ID out of %q: %v", b, err))
+	}
+	return n
+}
+
+var littleBuf = sync.Pool{
+	New: func() interface{} {
+		buf := make([]byte, 64)
+		return &buf
+	},
+}
+
+// parseUintBytes is like strconv.ParseUint, but using a []byte.
+func parseUintBytes(s []byte, base int, bitSize int) (n uint64, err error) {
+	var cutoff, maxVal uint64
+
+	if bitSize == 0 {
+		bitSize = int(strconv.IntSize)
+	}
+
+	s0 := s
+	switch {
+	case len(s) < 1:
+		err = strconv.ErrSyntax
+		goto Error
+
+	case 2 <= base && base <= 36:
+		// valid base; nothing to do
+
+	case base == 0:
+		// Look for octal, hex prefix.
+		switch {
+		case s[0] == '0' && len(s) > 1 && (s[1] == 'x' || s[1] == 'X'):
+			base = 16
+			s = s[2:]
+			if len(s) < 1 {
+				err = strconv.ErrSyntax
+				goto Error
+			}
+		case s[0] == '0':
+			base = 8
+		default:
+			base = 10
+		}
+
+	default:
+		err = errors.New("invalid base " + strconv.Itoa(base))
+		goto Error
+	}
+
+	n = 0
+	cutoff = cutoff64(base)
+	maxVal = 1<<uint(bitSize) - 1
+
+	for i := 0; i < len(s); i++ {
+		var v byte
+		d := s[i]
+		switch {
+		case '0' <= d && d <= '9':
+			v = d - '0'
+		case 'a' <= d && d <= 'z':
+			v = d - 'a' + 10
+		case 'A' <= d && d <= 'Z':
+			v = d - 'A' + 10
+		default:
+			n = 0
+			err = strconv.ErrSyntax
+			goto Error
+		}
+		if int(v) >= base {
+			n = 0
+			err = strconv.ErrSyntax
+			goto Error
+		}
+
+		if n >= cutoff {
+			// n*base overflows
+			n = 1<<64 - 1
+			err = strconv.ErrRange
+			goto Error
+		}
+		n *= uint64(base)
+
+		n1 := n + uint64(v)
+		if n1 < n || n1 > maxVal {
+			// n+v overflows
+			n = 1<<64 - 1
+			err = strconv.ErrRange
+			goto Error
+		}
+		n = n1
+	}
+
+	return n, nil
+
+Error:
+	return n, &strconv.NumError{Func: "ParseUint", Num: string(s0), Err: err}
+}
+
+// Return the first number n such that n*base >= 1<<64.
+func cutoff64(base int) uint64 {
+	if base < 2 {
+		return 0
+	}
+	return (1<<64-1)/uint64(base) + 1
+}
diff --git a/vendor/golang.org/x/net/http2/headermap.go b/vendor/golang.org/x/net/http2/headermap.go
new file mode 100644
index 0000000..c2805f6
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/headermap.go
@@ -0,0 +1,78 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http2
+
+import (
+	"net/http"
+	"strings"
+)
+
+var (
+	commonLowerHeader = map[string]string{} // Go-Canonical-Case -> lower-case
+	commonCanonHeader = map[string]string{} // lower-case -> Go-Canonical-Case
+)
+
+func init() {
+	for _, v := range []string{
+		"accept",
+		"accept-charset",
+		"accept-encoding",
+		"accept-language",
+		"accept-ranges",
+		"age",
+		"access-control-allow-origin",
+		"allow",
+		"authorization",
+		"cache-control",
+		"content-disposition",
+		"content-encoding",
+		"content-language",
+		"content-length",
+		"content-location",
+		"content-range",
+		"content-type",
+		"cookie",
+		"date",
+		"etag",
+		"expect",
+		"expires",
+		"from",
+		"host",
+		"if-match",
+		"if-modified-since",
+		"if-none-match",
+		"if-unmodified-since",
+		"last-modified",
+		"link",
+		"location",
+		"max-forwards",
+		"proxy-authenticate",
+		"proxy-authorization",
+		"range",
+		"referer",
+		"refresh",
+		"retry-after",
+		"server",
+		"set-cookie",
+		"strict-transport-security",
+		"trailer",
+		"transfer-encoding",
+		"user-agent",
+		"vary",
+		"via",
+		"www-authenticate",
+	} {
+		chk := http.CanonicalHeaderKey(v)
+		commonLowerHeader[chk] = v
+		commonCanonHeader[v] = chk
+	}
+}
+
+func lowerHeader(v string) string {
+	if s, ok := commonLowerHeader[v]; ok {
+		return s
+	}
+	return strings.ToLower(v)
+}
diff --git a/vendor/golang.org/x/net/http2/hpack/encode.go b/vendor/golang.org/x/net/http2/hpack/encode.go
new file mode 100644
index 0000000..f9bb033
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/hpack/encode.go
@@ -0,0 +1,251 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package hpack
+
+import (
+	"io"
+)
+
+const (
+	uint32Max              = ^uint32(0)
+	initialHeaderTableSize = 4096
+)
+
+type Encoder struct {
+	dynTab dynamicTable
+	// minSize is the minimum table size set by
+	// SetMaxDynamicTableSize after the previous Header Table Size
+	// Update.
+	minSize uint32
+	// maxSizeLimit is the maximum table size this encoder
+	// supports. This will protect the encoder from too large
+	// size.
+	maxSizeLimit uint32
+	// tableSizeUpdate indicates whether "Header Table Size
+	// Update" is required.
+	tableSizeUpdate bool
+	w               io.Writer
+	buf             []byte
+}
+
+// NewEncoder returns a new Encoder which performs HPACK encoding. An
+// encoded data is written to w.
+func NewEncoder(w io.Writer) *Encoder {
+	e := &Encoder{
+		minSize:         uint32Max,
+		maxSizeLimit:    initialHeaderTableSize,
+		tableSizeUpdate: false,
+		w:               w,
+	}
+	e.dynTab.setMaxSize(initialHeaderTableSize)
+	return e
+}
+
+// WriteField encodes f into a single Write to e's underlying Writer.
+// This function may also produce bytes for "Header Table Size Update"
+// if necessary.  If produced, it is done before encoding f.
+func (e *Encoder) WriteField(f HeaderField) error {
+	e.buf = e.buf[:0]
+
+	if e.tableSizeUpdate {
+		e.tableSizeUpdate = false
+		if e.minSize < e.dynTab.maxSize {
+			e.buf = appendTableSize(e.buf, e.minSize)
+		}
+		e.minSize = uint32Max
+		e.buf = appendTableSize(e.buf, e.dynTab.maxSize)
+	}
+
+	idx, nameValueMatch := e.searchTable(f)
+	if nameValueMatch {
+		e.buf = appendIndexed(e.buf, idx)
+	} else {
+		indexing := e.shouldIndex(f)
+		if indexing {
+			e.dynTab.add(f)
+		}
+
+		if idx == 0 {
+			e.buf = appendNewName(e.buf, f, indexing)
+		} else {
+			e.buf = appendIndexedName(e.buf, f, idx, indexing)
+		}
+	}
+	n, err := e.w.Write(e.buf)
+	if err == nil && n != len(e.buf) {
+		err = io.ErrShortWrite
+	}
+	return err
+}
+
+// searchTable searches f in both stable and dynamic header tables.
+// The static header table is searched first. Only when there is no
+// exact match for both name and value, the dynamic header table is
+// then searched. If there is no match, i is 0. If both name and value
+// match, i is the matched index and nameValueMatch becomes true. If
+// only name matches, i points to that index and nameValueMatch
+// becomes false.
+func (e *Encoder) searchTable(f HeaderField) (i uint64, nameValueMatch bool) {
+	for idx, hf := range staticTable {
+		if !constantTimeStringCompare(hf.Name, f.Name) {
+			continue
+		}
+		if i == 0 {
+			i = uint64(idx + 1)
+		}
+		if f.Sensitive {
+			continue
+		}
+		if !constantTimeStringCompare(hf.Value, f.Value) {
+			continue
+		}
+		i = uint64(idx + 1)
+		nameValueMatch = true
+		return
+	}
+
+	j, nameValueMatch := e.dynTab.search(f)
+	if nameValueMatch || (i == 0 && j != 0) {
+		i = j + uint64(len(staticTable))
+	}
+	return
+}
+
+// SetMaxDynamicTableSize changes the dynamic header table size to v.
+// The actual size is bounded by the value passed to
+// SetMaxDynamicTableSizeLimit.
+func (e *Encoder) SetMaxDynamicTableSize(v uint32) {
+	if v > e.maxSizeLimit {
+		v = e.maxSizeLimit
+	}
+	if v < e.minSize {
+		e.minSize = v
+	}
+	e.tableSizeUpdate = true
+	e.dynTab.setMaxSize(v)
+}
+
+// SetMaxDynamicTableSizeLimit changes the maximum value that can be
+// specified in SetMaxDynamicTableSize to v. By default, it is set to
+// 4096, which is the same size of the default dynamic header table
+// size described in HPACK specification. If the current maximum
+// dynamic header table size is strictly greater than v, "Header Table
+// Size Update" will be done in the next WriteField call and the
+// maximum dynamic header table size is truncated to v.
+func (e *Encoder) SetMaxDynamicTableSizeLimit(v uint32) {
+	e.maxSizeLimit = v
+	if e.dynTab.maxSize > v {
+		e.tableSizeUpdate = true
+		e.dynTab.setMaxSize(v)
+	}
+}
+
+// shouldIndex reports whether f should be indexed.
+func (e *Encoder) shouldIndex(f HeaderField) bool {
+	return !f.Sensitive && f.Size() <= e.dynTab.maxSize
+}
+
+// appendIndexed appends index i, as encoded in "Indexed Header Field"
+// representation, to dst and returns the extended buffer.
+func appendIndexed(dst []byte, i uint64) []byte {
+	first := len(dst)
+	dst = appendVarInt(dst, 7, i)
+	dst[first] |= 0x80
+	return dst
+}
+
+// appendNewName appends f, as encoded in one of "Literal Header field
+// - New Name" representation variants, to dst and returns the
+// extended buffer.
+//
+// If f.Sensitive is true, "Never Indexed" representation is used. If
+// f.Sensitive is false and indexing is true, "Inremental Indexing"
+// representation is used.
+func appendNewName(dst []byte, f HeaderField, indexing bool) []byte {
+	dst = append(dst, encodeTypeByte(indexing, f.Sensitive))
+	dst = appendHpackString(dst, f.Name)
+	return appendHpackString(dst, f.Value)
+}
+
+// appendIndexedName appends f and index i referring indexed name
+// entry, as encoded in one of "Literal Header field - Indexed Name"
+// representation variants, to dst and returns the extended buffer.
+//
+// If f.Sensitive is true, "Never Indexed" representation is used. If
+// f.Sensitive is false and indexing is true, "Incremental Indexing"
+// representation is used.
+func appendIndexedName(dst []byte, f HeaderField, i uint64, indexing bool) []byte {
+	first := len(dst)
+	var n byte
+	if indexing {
+		n = 6
+	} else {
+		n = 4
+	}
+	dst = appendVarInt(dst, n, i)
+	dst[first] |= encodeTypeByte(indexing, f.Sensitive)
+	return appendHpackString(dst, f.Value)
+}
+
+// appendTableSize appends v, as encoded in "Header Table Size Update"
+// representation, to dst and returns the extended buffer.
+func appendTableSize(dst []byte, v uint32) []byte {
+	first := len(dst)
+	dst = appendVarInt(dst, 5, uint64(v))
+	dst[first] |= 0x20
+	return dst
+}
+
+// appendVarInt appends i, as encoded in variable integer form using n
+// bit prefix, to dst and returns the extended buffer.
+//
+// See
+// http://http2.github.io/http2-spec/compression.html#integer.representation
+func appendVarInt(dst []byte, n byte, i uint64) []byte {
+	k := uint64((1 << n) - 1)
+	if i < k {
+		return append(dst, byte(i))
+	}
+	dst = append(dst, byte(k))
+	i -= k
+	for ; i >= 128; i >>= 7 {
+		dst = append(dst, byte(0x80|(i&0x7f)))
+	}
+	return append(dst, byte(i))
+}
+
+// appendHpackString appends s, as encoded in "String Literal"
+// representation, to dst and returns the the extended buffer.
+//
+// s will be encoded in Huffman codes only when it produces strictly
+// shorter byte string.
+func appendHpackString(dst []byte, s string) []byte {
+	huffmanLength := HuffmanEncodeLength(s)
+	if huffmanLength < uint64(len(s)) {
+		first := len(dst)
+		dst = appendVarInt(dst, 7, huffmanLength)
+		dst = AppendHuffmanString(dst, s)
+		dst[first] |= 0x80
+	} else {
+		dst = appendVarInt(dst, 7, uint64(len(s)))
+		dst = append(dst, s...)
+	}
+	return dst
+}
+
+// encodeTypeByte returns type byte. If sensitive is true, type byte
+// for "Never Indexed" representation is returned. If sensitive is
+// false and indexing is true, type byte for "Incremental Indexing"
+// representation is returned. Otherwise, type byte for "Without
+// Indexing" is returned.
+func encodeTypeByte(indexing, sensitive bool) byte {
+	if sensitive {
+		return 0x10
+	}
+	if indexing {
+		return 0x40
+	}
+	return 0
+}
diff --git a/vendor/golang.org/x/net/http2/hpack/hpack.go b/vendor/golang.org/x/net/http2/hpack/hpack.go
new file mode 100644
index 0000000..8aa197a
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/hpack/hpack.go
@@ -0,0 +1,542 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package hpack implements HPACK, a compression format for
+// efficiently representing HTTP header fields in the context of HTTP/2.
+//
+// See http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-09
+package hpack
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+)
+
+// A DecodingError is something the spec defines as a decoding error.
+type DecodingError struct {
+	Err error
+}
+
+func (de DecodingError) Error() string {
+	return fmt.Sprintf("decoding error: %v", de.Err)
+}
+
+// An InvalidIndexError is returned when an encoder references a table
+// entry before the static table or after the end of the dynamic table.
+type InvalidIndexError int
+
+func (e InvalidIndexError) Error() string {
+	return fmt.Sprintf("invalid indexed representation index %d", int(e))
+}
+
+// A HeaderField is a name-value pair. Both the name and value are
+// treated as opaque sequences of octets.
+type HeaderField struct {
+	Name, Value string
+
+	// Sensitive means that this header field should never be
+	// indexed.
+	Sensitive bool
+}
+
+// IsPseudo reports whether the header field is an http2 pseudo header.
+// That is, it reports whether it starts with a colon.
+// It is not otherwise guaranteed to be a valid pseudo header field,
+// though.
+func (hf HeaderField) IsPseudo() bool {
+	return len(hf.Name) != 0 && hf.Name[0] == ':'
+}
+
+func (hf HeaderField) String() string {
+	var suffix string
+	if hf.Sensitive {
+		suffix = " (sensitive)"
+	}
+	return fmt.Sprintf("header field %q = %q%s", hf.Name, hf.Value, suffix)
+}
+
+// Size returns the size of an entry per RFC 7540 section 5.2.
+func (hf HeaderField) Size() uint32 {
+	// http://http2.github.io/http2-spec/compression.html#rfc.section.4.1
+	// "The size of the dynamic table is the sum of the size of
+	// its entries.  The size of an entry is the sum of its name's
+	// length in octets (as defined in Section 5.2), its value's
+	// length in octets (see Section 5.2), plus 32.  The size of
+	// an entry is calculated using the length of the name and
+	// value without any Huffman encoding applied."
+
+	// This can overflow if somebody makes a large HeaderField
+	// Name and/or Value by hand, but we don't care, because that
+	// won't happen on the wire because the encoding doesn't allow
+	// it.
+	return uint32(len(hf.Name) + len(hf.Value) + 32)
+}
+
+// A Decoder is the decoding context for incremental processing of
+// header blocks.
+type Decoder struct {
+	dynTab dynamicTable
+	emit   func(f HeaderField)
+
+	emitEnabled bool // whether calls to emit are enabled
+	maxStrLen   int  // 0 means unlimited
+
+	// buf is the unparsed buffer. It's only written to
+	// saveBuf if it was truncated in the middle of a header
+	// block. Because it's usually not owned, we can only
+	// process it under Write.
+	buf []byte // not owned; only valid during Write
+
+	// saveBuf is previous data passed to Write which we weren't able
+	// to fully parse before. Unlike buf, we own this data.
+	saveBuf bytes.Buffer
+}
+
+// NewDecoder returns a new decoder with the provided maximum dynamic
+// table size. The emitFunc will be called for each valid field
+// parsed, in the same goroutine as calls to Write, before Write returns.
+func NewDecoder(maxDynamicTableSize uint32, emitFunc func(f HeaderField)) *Decoder {
+	d := &Decoder{
+		emit:        emitFunc,
+		emitEnabled: true,
+	}
+	d.dynTab.allowedMaxSize = maxDynamicTableSize
+	d.dynTab.setMaxSize(maxDynamicTableSize)
+	return d
+}
+
+// ErrStringLength is returned by Decoder.Write when the max string length
+// (as configured by Decoder.SetMaxStringLength) would be violated.
+var ErrStringLength = errors.New("hpack: string too long")
+
+// SetMaxStringLength sets the maximum size of a HeaderField name or
+// value string. If a string exceeds this length (even after any
+// decompression), Write will return ErrStringLength.
+// A value of 0 means unlimited and is the default from NewDecoder.
+func (d *Decoder) SetMaxStringLength(n int) {
+	d.maxStrLen = n
+}
+
+// SetEmitFunc changes the callback used when new header fields
+// are decoded.
+// It must be non-nil. It does not affect EmitEnabled.
+func (d *Decoder) SetEmitFunc(emitFunc func(f HeaderField)) {
+	d.emit = emitFunc
+}
+
+// SetEmitEnabled controls whether the emitFunc provided to NewDecoder
+// should be called. The default is true.
+//
+// This facility exists to let servers enforce MAX_HEADER_LIST_SIZE
+// while still decoding and keeping in-sync with decoder state, but
+// without doing unnecessary decompression or generating unnecessary
+// garbage for header fields past the limit.
+func (d *Decoder) SetEmitEnabled(v bool) { d.emitEnabled = v }
+
+// EmitEnabled reports whether calls to the emitFunc provided to NewDecoder
+// are currently enabled. The default is true.
+func (d *Decoder) EmitEnabled() bool { return d.emitEnabled }
+
+// TODO: add method *Decoder.Reset(maxSize, emitFunc) to let callers re-use Decoders and their
+// underlying buffers for garbage reasons.
+
+func (d *Decoder) SetMaxDynamicTableSize(v uint32) {
+	d.dynTab.setMaxSize(v)
+}
+
+// SetAllowedMaxDynamicTableSize sets the upper bound that the encoded
+// stream (via dynamic table size updates) may set the maximum size
+// to.
+func (d *Decoder) SetAllowedMaxDynamicTableSize(v uint32) {
+	d.dynTab.allowedMaxSize = v
+}
+
+type dynamicTable struct {
+	// ents is the FIFO described at
+	// http://http2.github.io/http2-spec/compression.html#rfc.section.2.3.2
+	// The newest (low index) is append at the end, and items are
+	// evicted from the front.
+	ents           []HeaderField
+	size           uint32
+	maxSize        uint32 // current maxSize
+	allowedMaxSize uint32 // maxSize may go up to this, inclusive
+}
+
+func (dt *dynamicTable) setMaxSize(v uint32) {
+	dt.maxSize = v
+	dt.evict()
+}
+
+// TODO: change dynamicTable to be a struct with a slice and a size int field,
+// per http://http2.github.io/http2-spec/compression.html#rfc.section.4.1:
+//
+//
+// Then make add increment the size. maybe the max size should move from Decoder to
+// dynamicTable and add should return an ok bool if there was enough space.
+//
+// Later we'll need a remove operation on dynamicTable.
+
+func (dt *dynamicTable) add(f HeaderField) {
+	dt.ents = append(dt.ents, f)
+	dt.size += f.Size()
+	dt.evict()
+}
+
+// If we're too big, evict old stuff (front of the slice)
+func (dt *dynamicTable) evict() {
+	base := dt.ents // keep base pointer of slice
+	for dt.size > dt.maxSize {
+		dt.size -= dt.ents[0].Size()
+		dt.ents = dt.ents[1:]
+	}
+
+	// Shift slice contents down if we evicted things.
+	if len(dt.ents) != len(base) {
+		copy(base, dt.ents)
+		dt.ents = base[:len(dt.ents)]
+	}
+}
+
+// constantTimeStringCompare compares string a and b in a constant
+// time manner.
+func constantTimeStringCompare(a, b string) bool {
+	if len(a) != len(b) {
+		return false
+	}
+
+	c := byte(0)
+
+	for i := 0; i < len(a); i++ {
+		c |= a[i] ^ b[i]
+	}
+
+	return c == 0
+}
+
+// Search searches f in the table. The return value i is 0 if there is
+// no name match. If there is name match or name/value match, i is the
+// index of that entry (1-based). If both name and value match,
+// nameValueMatch becomes true.
+func (dt *dynamicTable) search(f HeaderField) (i uint64, nameValueMatch bool) {
+	l := len(dt.ents)
+	for j := l - 1; j >= 0; j-- {
+		ent := dt.ents[j]
+		if !constantTimeStringCompare(ent.Name, f.Name) {
+			continue
+		}
+		if i == 0 {
+			i = uint64(l - j)
+		}
+		if f.Sensitive {
+			continue
+		}
+		if !constantTimeStringCompare(ent.Value, f.Value) {
+			continue
+		}
+		i = uint64(l - j)
+		nameValueMatch = true
+		return
+	}
+	return
+}
+
+func (d *Decoder) maxTableIndex() int {
+	return len(d.dynTab.ents) + len(staticTable)
+}
+
+func (d *Decoder) at(i uint64) (hf HeaderField, ok bool) {
+	if i < 1 {
+		return
+	}
+	if i > uint64(d.maxTableIndex()) {
+		return
+	}
+	if i <= uint64(len(staticTable)) {
+		return staticTable[i-1], true
+	}
+	dents := d.dynTab.ents
+	return dents[len(dents)-(int(i)-len(staticTable))], true
+}
+
+// Decode decodes an entire block.
+//
+// TODO: remove this method and make it incremental later? This is
+// easier for debugging now.
+func (d *Decoder) DecodeFull(p []byte) ([]HeaderField, error) {
+	var hf []HeaderField
+	saveFunc := d.emit
+	defer func() { d.emit = saveFunc }()
+	d.emit = func(f HeaderField) { hf = append(hf, f) }
+	if _, err := d.Write(p); err != nil {
+		return nil, err
+	}
+	if err := d.Close(); err != nil {
+		return nil, err
+	}
+	return hf, nil
+}
+
+func (d *Decoder) Close() error {
+	if d.saveBuf.Len() > 0 {
+		d.saveBuf.Reset()
+		return DecodingError{errors.New("truncated headers")}
+	}
+	return nil
+}
+
+func (d *Decoder) Write(p []byte) (n int, err error) {
+	if len(p) == 0 {
+		// Prevent state machine CPU attacks (making us redo
+		// work up to the point of finding out we don't have
+		// enough data)
+		return
+	}
+	// Only copy the data if we have to. Optimistically assume
+	// that p will contain a complete header block.
+	if d.saveBuf.Len() == 0 {
+		d.buf = p
+	} else {
+		d.saveBuf.Write(p)
+		d.buf = d.saveBuf.Bytes()
+		d.saveBuf.Reset()
+	}
+
+	for len(d.buf) > 0 {
+		err = d.parseHeaderFieldRepr()
+		if err == errNeedMore {
+			// Extra paranoia, making sure saveBuf won't
+			// get too large.  All the varint and string
+			// reading code earlier should already catch
+			// overlong things and return ErrStringLength,
+			// but keep this as a last resort.
+			const varIntOverhead = 8 // conservative
+			if d.maxStrLen != 0 && int64(len(d.buf)) > 2*(int64(d.maxStrLen)+varIntOverhead) {
+				return 0, ErrStringLength
+			}
+			d.saveBuf.Write(d.buf)
+			return len(p), nil
+		}
+		if err != nil {
+			break
+		}
+	}
+	return len(p), err
+}
+
+// errNeedMore is an internal sentinel error value that means the
+// buffer is truncated and we need to read more data before we can
+// continue parsing.
+var errNeedMore = errors.New("need more data")
+
+type indexType int
+
+const (
+	indexedTrue indexType = iota
+	indexedFalse
+	indexedNever
+)
+
+func (v indexType) indexed() bool   { return v == indexedTrue }
+func (v indexType) sensitive() bool { return v == indexedNever }
+
+// returns errNeedMore if there isn't enough data available.
+// any other error is fatal.
+// consumes d.buf iff it returns nil.
+// precondition: must be called with len(d.buf) > 0
+func (d *Decoder) parseHeaderFieldRepr() error {
+	b := d.buf[0]
+	switch {
+	case b&128 != 0:
+		// Indexed representation.
+		// High bit set?
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.6.1
+		return d.parseFieldIndexed()
+	case b&192 == 64:
+		// 6.2.1 Literal Header Field with Incremental Indexing
+		// 0b10xxxxxx: top two bits are 10
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.6.2.1
+		return d.parseFieldLiteral(6, indexedTrue)
+	case b&240 == 0:
+		// 6.2.2 Literal Header Field without Indexing
+		// 0b0000xxxx: top four bits are 0000
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.6.2.2
+		return d.parseFieldLiteral(4, indexedFalse)
+	case b&240 == 16:
+		// 6.2.3 Literal Header Field never Indexed
+		// 0b0001xxxx: top four bits are 0001
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.6.2.3
+		return d.parseFieldLiteral(4, indexedNever)
+	case b&224 == 32:
+		// 6.3 Dynamic Table Size Update
+		// Top three bits are '001'.
+		// http://http2.github.io/http2-spec/compression.html#rfc.section.6.3
+		return d.parseDynamicTableSizeUpdate()
+	}
+
+	return DecodingError{errors.New("invalid encoding")}
+}
+
+// (same invariants and behavior as parseHeaderFieldRepr)
+func (d *Decoder) parseFieldIndexed() error {
+	buf := d.buf
+	idx, buf, err := readVarInt(7, buf)
+	if err != nil {
+		return err
+	}
+	hf, ok := d.at(idx)
+	if !ok {
+		return DecodingError{InvalidIndexError(idx)}
+	}
+	d.buf = buf
+	return d.callEmit(HeaderField{Name: hf.Name, Value: hf.Value})
+}
+
+// (same invariants and behavior as parseHeaderFieldRepr)
+func (d *Decoder) parseFieldLiteral(n uint8, it indexType) error {
+	buf := d.buf
+	nameIdx, buf, err := readVarInt(n, buf)
+	if err != nil {
+		return err
+	}
+
+	var hf HeaderField
+	wantStr := d.emitEnabled || it.indexed()
+	if nameIdx > 0 {
+		ihf, ok := d.at(nameIdx)
+		if !ok {
+			return DecodingError{InvalidIndexError(nameIdx)}
+		}
+		hf.Name = ihf.Name
+	} else {
+		hf.Name, buf, err = d.readString(buf, wantStr)
+		if err != nil {
+			return err
+		}
+	}
+	hf.Value, buf, err = d.readString(buf, wantStr)
+	if err != nil {
+		return err
+	}
+	d.buf = buf
+	if it.indexed() {
+		d.dynTab.add(hf)
+	}
+	hf.Sensitive = it.sensitive()
+	return d.callEmit(hf)
+}
+
+func (d *Decoder) callEmit(hf HeaderField) error {
+	if d.maxStrLen != 0 {
+		if len(hf.Name) > d.maxStrLen || len(hf.Value) > d.maxStrLen {
+			return ErrStringLength
+		}
+	}
+	if d.emitEnabled {
+		d.emit(hf)
+	}
+	return nil
+}
+
+// (same invariants and behavior as parseHeaderFieldRepr)
+func (d *Decoder) parseDynamicTableSizeUpdate() error {
+	buf := d.buf
+	size, buf, err := readVarInt(5, buf)
+	if err != nil {
+		return err
+	}
+	if size > uint64(d.dynTab.allowedMaxSize) {
+		return DecodingError{errors.New("dynamic table size update too large")}
+	}
+	d.dynTab.setMaxSize(uint32(size))
+	d.buf = buf
+	return nil
+}
+
+var errVarintOverflow = DecodingError{errors.New("varint integer overflow")}
+
+// readVarInt reads an unsigned variable length integer off the
+// beginning of p. n is the parameter as described in
+// http://http2.github.io/http2-spec/compression.html#rfc.section.5.1.
+//
+// n must always be between 1 and 8.
+//
+// The returned remain buffer is either a smaller suffix of p, or err != nil.
+// The error is errNeedMore if p doesn't contain a complete integer.
+func readVarInt(n byte, p []byte) (i uint64, remain []byte, err error) {
+	if n < 1 || n > 8 {
+		panic("bad n")
+	}
+	if len(p) == 0 {
+		return 0, p, errNeedMore
+	}
+	i = uint64(p[0])
+	if n < 8 {
+		i &= (1 << uint64(n)) - 1
+	}
+	if i < (1<<uint64(n))-1 {
+		return i, p[1:], nil
+	}
+
+	origP := p
+	p = p[1:]
+	var m uint64
+	for len(p) > 0 {
+		b := p[0]
+		p = p[1:]
+		i += uint64(b&127) << m
+		if b&128 == 0 {
+			return i, p, nil
+		}
+		m += 7
+		if m >= 63 { // TODO: proper overflow check. making this up.
+			return 0, origP, errVarintOverflow
+		}
+	}
+	return 0, origP, errNeedMore
+}
+
+// readString decodes an hpack string from p.
+//
+// wantStr is whether s will be used. If false, decompression and
+// []byte->string garbage are skipped if s will be ignored
+// anyway. This does mean that huffman decoding errors for non-indexed
+// strings past the MAX_HEADER_LIST_SIZE are ignored, but the server
+// is returning an error anyway, and because they're not indexed, the error
+// won't affect the decoding state.
+func (d *Decoder) readString(p []byte, wantStr bool) (s string, remain []byte, err error) {
+	if len(p) == 0 {
+		return "", p, errNeedMore
+	}
+	isHuff := p[0]&128 != 0
+	strLen, p, err := readVarInt(7, p)
+	if err != nil {
+		return "", p, err
+	}
+	if d.maxStrLen != 0 && strLen > uint64(d.maxStrLen) {
+		return "", nil, ErrStringLength
+	}
+	if uint64(len(p)) < strLen {
+		return "", p, errNeedMore
+	}
+	if !isHuff {
+		if wantStr {
+			s = string(p[:strLen])
+		}
+		return s, p[strLen:], nil
+	}
+
+	if wantStr {
+		buf := bufPool.Get().(*bytes.Buffer)
+		buf.Reset() // don't trust others
+		defer bufPool.Put(buf)
+		if err := huffmanDecode(buf, d.maxStrLen, p[:strLen]); err != nil {
+			buf.Reset()
+			return "", nil, err
+		}
+		s = buf.String()
+		buf.Reset() // be nice to GC
+	}
+	return s, p[strLen:], nil
+}
diff --git a/vendor/golang.org/x/net/http2/hpack/huffman.go b/vendor/golang.org/x/net/http2/hpack/huffman.go
new file mode 100644
index 0000000..8850e39
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/hpack/huffman.go
@@ -0,0 +1,212 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package hpack
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"sync"
+)
+
+var bufPool = sync.Pool{
+	New: func() interface{} { return new(bytes.Buffer) },
+}
+
+// HuffmanDecode decodes the string in v and writes the expanded
+// result to w, returning the number of bytes written to w and the
+// Write call's return value. At most one Write call is made.
+func HuffmanDecode(w io.Writer, v []byte) (int, error) {
+	buf := bufPool.Get().(*bytes.Buffer)
+	buf.Reset()
+	defer bufPool.Put(buf)
+	if err := huffmanDecode(buf, 0, v); err != nil {
+		return 0, err
+	}
+	return w.Write(buf.Bytes())
+}
+
+// HuffmanDecodeToString decodes the string in v.
+func HuffmanDecodeToString(v []byte) (string, error) {
+	buf := bufPool.Get().(*bytes.Buffer)
+	buf.Reset()
+	defer bufPool.Put(buf)
+	if err := huffmanDecode(buf, 0, v); err != nil {
+		return "", err
+	}
+	return buf.String(), nil
+}
+
+// ErrInvalidHuffman is returned for errors found decoding
+// Huffman-encoded strings.
+var ErrInvalidHuffman = errors.New("hpack: invalid Huffman-encoded data")
+
+// huffmanDecode decodes v to buf.
+// If maxLen is greater than 0, attempts to write more to buf than
+// maxLen bytes will return ErrStringLength.
+func huffmanDecode(buf *bytes.Buffer, maxLen int, v []byte) error {
+	n := rootHuffmanNode
+	// cur is the bit buffer that has not been fed into n.
+	// cbits is the number of low order bits in cur that are valid.
+	// sbits is the number of bits of the symbol prefix being decoded.
+	cur, cbits, sbits := uint(0), uint8(0), uint8(0)
+	for _, b := range v {
+		cur = cur<<8 | uint(b)
+		cbits += 8
+		sbits += 8
+		for cbits >= 8 {
+			idx := byte(cur >> (cbits - 8))
+			n = n.children[idx]
+			if n == nil {
+				return ErrInvalidHuffman
+			}
+			if n.children == nil {
+				if maxLen != 0 && buf.Len() == maxLen {
+					return ErrStringLength
+				}
+				buf.WriteByte(n.sym)
+				cbits -= n.codeLen
+				n = rootHuffmanNode
+				sbits = cbits
+			} else {
+				cbits -= 8
+			}
+		}
+	}
+	for cbits > 0 {
+		n = n.children[byte(cur<<(8-cbits))]
+		if n == nil {
+			return ErrInvalidHuffman
+		}
+		if n.children != nil || n.codeLen > cbits {
+			break
+		}
+		if maxLen != 0 && buf.Len() == maxLen {
+			return ErrStringLength
+		}
+		buf.WriteByte(n.sym)
+		cbits -= n.codeLen
+		n = rootHuffmanNode
+		sbits = cbits
+	}
+	if sbits > 7 {
+		// Either there was an incomplete symbol, or overlong padding.
+		// Both are decoding errors per RFC 7541 section 5.2.
+		return ErrInvalidHuffman
+	}
+	if mask := uint(1<<cbits - 1); cur&mask != mask {
+		// Trailing bits must be a prefix of EOS per RFC 7541 section 5.2.
+		return ErrInvalidHuffman
+	}
+
+	return nil
+}
+
+type node struct {
+	// children is non-nil for internal nodes
+	children []*node
+
+	// The following are only valid if children is nil:
+	codeLen uint8 // number of bits that led to the output of sym
+	sym     byte  // output symbol
+}
+
+func newInternalNode() *node {
+	return &node{children: make([]*node, 256)}
+}
+
+var rootHuffmanNode = newInternalNode()
+
+func init() {
+	if len(huffmanCodes) != 256 {
+		panic("unexpected size")
+	}
+	for i, code := range huffmanCodes {
+		addDecoderNode(byte(i), code, huffmanCodeLen[i])
+	}
+}
+
+func addDecoderNode(sym byte, code uint32, codeLen uint8) {
+	cur := rootHuffmanNode
+	for codeLen > 8 {
+		codeLen -= 8
+		i := uint8(code >> codeLen)
+		if cur.children[i] == nil {
+			cur.children[i] = newInternalNode()
+		}
+		cur = cur.children[i]
+	}
+	shift := 8 - codeLen
+	start, end := int(uint8(code<<shift)), int(1<<shift)
+	for i := start; i < start+end; i++ {
+		cur.children[i] = &node{sym: sym, codeLen: codeLen}
+	}
+}
+
+// AppendHuffmanString appends s, as encoded in Huffman codes, to dst
+// and returns the extended buffer.
+func AppendHuffmanString(dst []byte, s string) []byte {
+	rembits := uint8(8)
+
+	for i := 0; i < len(s); i++ {
+		if rembits == 8 {
+			dst = append(dst, 0)
+		}
+		dst, rembits = appendByteToHuffmanCode(dst, rembits, s[i])
+	}
+
+	if rembits < 8 {
+		// special EOS symbol
+		code := uint32(0x3fffffff)
+		nbits := uint8(30)
+
+		t := uint8(code >> (nbits - rembits))
+		dst[len(dst)-1] |= t
+	}
+
+	return dst
+}
+
+// HuffmanEncodeLength returns the number of bytes required to encode
+// s in Huffman codes. The result is round up to byte boundary.
+func HuffmanEncodeLength(s string) uint64 {
+	n := uint64(0)
+	for i := 0; i < len(s); i++ {
+		n += uint64(huffmanCodeLen[s[i]])
+	}
+	return (n + 7) / 8
+}
+
+// appendByteToHuffmanCode appends Huffman code for c to dst and
+// returns the extended buffer and the remaining bits in the last
+// element. The appending is not byte aligned and the remaining bits
+// in the last element of dst is given in rembits.
+func appendByteToHuffmanCode(dst []byte, rembits uint8, c byte) ([]byte, uint8) {
+	code := huffmanCodes[c]
+	nbits := huffmanCodeLen[c]
+
+	for {
+		if rembits > nbits {
+			t := uint8(code << (rembits - nbits))
+			dst[len(dst)-1] |= t
+			rembits -= nbits
+			break
+		}
+
+		t := uint8(code >> (nbits - rembits))
+		dst[len(dst)-1] |= t
+
+		nbits -= rembits
+		rembits = 8
+
+		if nbits == 0 {
+			break
+		}
+
+		dst = append(dst, 0)
+	}
+
+	return dst, rembits
+}
diff --git a/vendor/golang.org/x/net/http2/hpack/tables.go b/vendor/golang.org/x/net/http2/hpack/tables.go
new file mode 100644
index 0000000..b9283a0
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/hpack/tables.go
@@ -0,0 +1,352 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package hpack
+
+func pair(name, value string) HeaderField {
+	return HeaderField{Name: name, Value: value}
+}
+
+// http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-07#appendix-B
+var staticTable = [...]HeaderField{
+	pair(":authority", ""), // index 1 (1-based)
+	pair(":method", "GET"),
+	pair(":method", "POST"),
+	pair(":path", "/"),
+	pair(":path", "/index.html"),
+	pair(":scheme", "http"),
+	pair(":scheme", "https"),
+	pair(":status", "200"),
+	pair(":status", "204"),
+	pair(":status", "206"),
+	pair(":status", "304"),
+	pair(":status", "400"),
+	pair(":status", "404"),
+	pair(":status", "500"),
+	pair("accept-charset", ""),
+	pair("accept-encoding", "gzip, deflate"),
+	pair("accept-language", ""),
+	pair("accept-ranges", ""),
+	pair("accept", ""),
+	pair("access-control-allow-origin", ""),
+	pair("age", ""),
+	pair("allow", ""),
+	pair("authorization", ""),
+	pair("cache-control", ""),
+	pair("content-disposition", ""),
+	pair("content-encoding", ""),
+	pair("content-language", ""),
+	pair("content-length", ""),
+	pair("content-location", ""),
+	pair("content-range", ""),
+	pair("content-type", ""),
+	pair("cookie", ""),
+	pair("date", ""),
+	pair("etag", ""),
+	pair("expect", ""),
+	pair("expires", ""),
+	pair("from", ""),
+	pair("host", ""),
+	pair("if-match", ""),
+	pair("if-modified-since", ""),
+	pair("if-none-match", ""),
+	pair("if-range", ""),
+	pair("if-unmodified-since", ""),
+	pair("last-modified", ""),
+	pair("link", ""),
+	pair("location", ""),
+	pair("max-forwards", ""),
+	pair("proxy-authenticate", ""),
+	pair("proxy-authorization", ""),
+	pair("range", ""),
+	pair("referer", ""),
+	pair("refresh", ""),
+	pair("retry-after", ""),
+	pair("server", ""),
+	pair("set-cookie", ""),
+	pair("strict-transport-security", ""),
+	pair("transfer-encoding", ""),
+	pair("user-agent", ""),
+	pair("vary", ""),
+	pair("via", ""),
+	pair("www-authenticate", ""),
+}
+
+var huffmanCodes = [256]uint32{
+	0x1ff8,
+	0x7fffd8,
+	0xfffffe2,
+	0xfffffe3,
+	0xfffffe4,
+	0xfffffe5,
+	0xfffffe6,
+	0xfffffe7,
+	0xfffffe8,
+	0xffffea,
+	0x3ffffffc,
+	0xfffffe9,
+	0xfffffea,
+	0x3ffffffd,
+	0xfffffeb,
+	0xfffffec,
+	0xfffffed,
+	0xfffffee,
+	0xfffffef,
+	0xffffff0,
+	0xffffff1,
+	0xffffff2,
+	0x3ffffffe,
+	0xffffff3,
+	0xffffff4,
+	0xffffff5,
+	0xffffff6,
+	0xffffff7,
+	0xffffff8,
+	0xffffff9,
+	0xffffffa,
+	0xffffffb,
+	0x14,
+	0x3f8,
+	0x3f9,
+	0xffa,
+	0x1ff9,
+	0x15,
+	0xf8,
+	0x7fa,
+	0x3fa,
+	0x3fb,
+	0xf9,
+	0x7fb,
+	0xfa,
+	0x16,
+	0x17,
+	0x18,
+	0x0,
+	0x1,
+	0x2,
+	0x19,
+	0x1a,
+	0x1b,
+	0x1c,
+	0x1d,
+	0x1e,
+	0x1f,
+	0x5c,
+	0xfb,
+	0x7ffc,
+	0x20,
+	0xffb,
+	0x3fc,
+	0x1ffa,
+	0x21,
+	0x5d,
+	0x5e,
+	0x5f,
+	0x60,
+	0x61,
+	0x62,
+	0x63,
+	0x64,
+	0x65,
+	0x66,
+	0x67,
+	0x68,
+	0x69,
+	0x6a,
+	0x6b,
+	0x6c,
+	0x6d,
+	0x6e,
+	0x6f,
+	0x70,
+	0x71,
+	0x72,
+	0xfc,
+	0x73,
+	0xfd,
+	0x1ffb,
+	0x7fff0,
+	0x1ffc,
+	0x3ffc,
+	0x22,
+	0x7ffd,
+	0x3,
+	0x23,
+	0x4,
+	0x24,
+	0x5,
+	0x25,
+	0x26,
+	0x27,
+	0x6,
+	0x74,
+	0x75,
+	0x28,
+	0x29,
+	0x2a,
+	0x7,
+	0x2b,
+	0x76,
+	0x2c,
+	0x8,
+	0x9,
+	0x2d,
+	0x77,
+	0x78,
+	0x79,
+	0x7a,
+	0x7b,
+	0x7ffe,
+	0x7fc,
+	0x3ffd,
+	0x1ffd,
+	0xffffffc,
+	0xfffe6,
+	0x3fffd2,
+	0xfffe7,
+	0xfffe8,
+	0x3fffd3,
+	0x3fffd4,
+	0x3fffd5,
+	0x7fffd9,
+	0x3fffd6,
+	0x7fffda,
+	0x7fffdb,
+	0x7fffdc,
+	0x7fffdd,
+	0x7fffde,
+	0xffffeb,
+	0x7fffdf,
+	0xffffec,
+	0xffffed,
+	0x3fffd7,
+	0x7fffe0,
+	0xffffee,
+	0x7fffe1,
+	0x7fffe2,
+	0x7fffe3,
+	0x7fffe4,
+	0x1fffdc,
+	0x3fffd8,
+	0x7fffe5,
+	0x3fffd9,
+	0x7fffe6,
+	0x7fffe7,
+	0xffffef,
+	0x3fffda,
+	0x1fffdd,
+	0xfffe9,
+	0x3fffdb,
+	0x3fffdc,
+	0x7fffe8,
+	0x7fffe9,
+	0x1fffde,
+	0x7fffea,
+	0x3fffdd,
+	0x3fffde,
+	0xfffff0,
+	0x1fffdf,
+	0x3fffdf,
+	0x7fffeb,
+	0x7fffec,
+	0x1fffe0,
+	0x1fffe1,
+	0x3fffe0,
+	0x1fffe2,
+	0x7fffed,
+	0x3fffe1,
+	0x7fffee,
+	0x7fffef,
+	0xfffea,
+	0x3fffe2,
+	0x3fffe3,
+	0x3fffe4,
+	0x7ffff0,
+	0x3fffe5,
+	0x3fffe6,
+	0x7ffff1,
+	0x3ffffe0,
+	0x3ffffe1,
+	0xfffeb,
+	0x7fff1,
+	0x3fffe7,
+	0x7ffff2,
+	0x3fffe8,
+	0x1ffffec,
+	0x3ffffe2,
+	0x3ffffe3,
+	0x3ffffe4,
+	0x7ffffde,
+	0x7ffffdf,
+	0x3ffffe5,
+	0xfffff1,
+	0x1ffffed,
+	0x7fff2,
+	0x1fffe3,
+	0x3ffffe6,
+	0x7ffffe0,
+	0x7ffffe1,
+	0x3ffffe7,
+	0x7ffffe2,
+	0xfffff2,
+	0x1fffe4,
+	0x1fffe5,
+	0x3ffffe8,
+	0x3ffffe9,
+	0xffffffd,
+	0x7ffffe3,
+	0x7ffffe4,
+	0x7ffffe5,
+	0xfffec,
+	0xfffff3,
+	0xfffed,
+	0x1fffe6,
+	0x3fffe9,
+	0x1fffe7,
+	0x1fffe8,
+	0x7ffff3,
+	0x3fffea,
+	0x3fffeb,
+	0x1ffffee,
+	0x1ffffef,
+	0xfffff4,
+	0xfffff5,
+	0x3ffffea,
+	0x7ffff4,
+	0x3ffffeb,
+	0x7ffffe6,
+	0x3ffffec,
+	0x3ffffed,
+	0x7ffffe7,
+	0x7ffffe8,
+	0x7ffffe9,
+	0x7ffffea,
+	0x7ffffeb,
+	0xffffffe,
+	0x7ffffec,
+	0x7ffffed,
+	0x7ffffee,
+	0x7ffffef,
+	0x7fffff0,
+	0x3ffffee,
+}
+
+var huffmanCodeLen = [256]uint8{
+	13, 23, 28, 28, 28, 28, 28, 28, 28, 24, 30, 28, 28, 30, 28, 28,
+	28, 28, 28, 28, 28, 28, 30, 28, 28, 28, 28, 28, 28, 28, 28, 28,
+	6, 10, 10, 12, 13, 6, 8, 11, 10, 10, 8, 11, 8, 6, 6, 6,
+	5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 8, 15, 6, 12, 10,
+	13, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+	7, 7, 7, 7, 7, 7, 7, 7, 8, 7, 8, 13, 19, 13, 14, 6,
+	15, 5, 6, 5, 6, 5, 6, 6, 6, 5, 7, 7, 6, 6, 6, 5,
+	6, 7, 6, 5, 5, 6, 7, 7, 7, 7, 7, 15, 11, 14, 13, 28,
+	20, 22, 20, 20, 22, 22, 22, 23, 22, 23, 23, 23, 23, 23, 24, 23,
+	24, 24, 22, 23, 24, 23, 23, 23, 23, 21, 22, 23, 22, 23, 23, 24,
+	22, 21, 20, 22, 22, 23, 23, 21, 23, 22, 22, 24, 21, 22, 23, 23,
+	21, 21, 22, 21, 23, 22, 23, 23, 20, 22, 22, 22, 23, 22, 22, 23,
+	26, 26, 20, 19, 22, 23, 22, 25, 26, 26, 26, 27, 27, 26, 24, 25,
+	19, 21, 26, 27, 27, 26, 27, 24, 21, 21, 26, 26, 28, 27, 27, 27,
+	20, 24, 20, 21, 22, 21, 21, 23, 22, 22, 25, 25, 24, 24, 26, 23,
+	26, 27, 26, 26, 27, 27, 27, 27, 27, 28, 27, 27, 27, 27, 27, 26,
+}
diff --git a/vendor/golang.org/x/net/http2/http2.go b/vendor/golang.org/x/net/http2/http2.go
new file mode 100644
index 0000000..0173aed
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/http2.go
@@ -0,0 +1,351 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package http2 implements the HTTP/2 protocol.
+//
+// This package is low-level and intended to be used directly by very
+// few people. Most users will use it indirectly through the automatic
+// use by the net/http package (from Go 1.6 and later).
+// For use in earlier Go versions see ConfigureServer. (Transport support
+// requires Go 1.6 or later)
+//
+// See https://http2.github.io/ for more information on HTTP/2.
+//
+// See https://http2.golang.org/ for a test server running this code.
+package http2
+
+import (
+	"bufio"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"sort"
+	"strconv"
+	"strings"
+	"sync"
+
+	"golang.org/x/net/lex/httplex"
+)
+
+var (
+	VerboseLogs    bool
+	logFrameWrites bool
+	logFrameReads  bool
+)
+
+func init() {
+	e := os.Getenv("GODEBUG")
+	if strings.Contains(e, "http2debug=1") {
+		VerboseLogs = true
+	}
+	if strings.Contains(e, "http2debug=2") {
+		VerboseLogs = true
+		logFrameWrites = true
+		logFrameReads = true
+	}
+}
+
+const (
+	// ClientPreface is the string that must be sent by new
+	// connections from clients.
+	ClientPreface = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n"
+
+	// SETTINGS_MAX_FRAME_SIZE default
+	// http://http2.github.io/http2-spec/#rfc.section.6.5.2
+	initialMaxFrameSize = 16384
+
+	// NextProtoTLS is the NPN/ALPN protocol negotiated during
+	// HTTP/2's TLS setup.
+	NextProtoTLS = "h2"
+
+	// http://http2.github.io/http2-spec/#SettingValues
+	initialHeaderTableSize = 4096
+
+	initialWindowSize = 65535 // 6.9.2 Initial Flow Control Window Size
+
+	defaultMaxReadFrameSize = 1 << 20
+)
+
+var (
+	clientPreface = []byte(ClientPreface)
+)
+
+type streamState int
+
+const (
+	stateIdle streamState = iota
+	stateOpen
+	stateHalfClosedLocal
+	stateHalfClosedRemote
+	stateResvLocal
+	stateResvRemote
+	stateClosed
+)
+
+var stateName = [...]string{
+	stateIdle:             "Idle",
+	stateOpen:             "Open",
+	stateHalfClosedLocal:  "HalfClosedLocal",
+	stateHalfClosedRemote: "HalfClosedRemote",
+	stateResvLocal:        "ResvLocal",
+	stateResvRemote:       "ResvRemote",
+	stateClosed:           "Closed",
+}
+
+func (st streamState) String() string {
+	return stateName[st]
+}
+
+// Setting is a setting parameter: which setting it is, and its value.
+type Setting struct {
+	// ID is which setting is being set.
+	// See http://http2.github.io/http2-spec/#SettingValues
+	ID SettingID
+
+	// Val is the value.
+	Val uint32
+}
+
+func (s Setting) String() string {
+	return fmt.Sprintf("[%v = %d]", s.ID, s.Val)
+}
+
+// Valid reports whether the setting is valid.
+func (s Setting) Valid() error {
+	// Limits and error codes from 6.5.2 Defined SETTINGS Parameters
+	switch s.ID {
+	case SettingEnablePush:
+		if s.Val != 1 && s.Val != 0 {
+			return ConnectionError(ErrCodeProtocol)
+		}
+	case SettingInitialWindowSize:
+		if s.Val > 1<<31-1 {
+			return ConnectionError(ErrCodeFlowControl)
+		}
+	case SettingMaxFrameSize:
+		if s.Val < 16384 || s.Val > 1<<24-1 {
+			return ConnectionError(ErrCodeProtocol)
+		}
+	}
+	return nil
+}
+
+// A SettingID is an HTTP/2 setting as defined in
+// http://http2.github.io/http2-spec/#iana-settings
+type SettingID uint16
+
+const (
+	SettingHeaderTableSize      SettingID = 0x1
+	SettingEnablePush           SettingID = 0x2
+	SettingMaxConcurrentStreams SettingID = 0x3
+	SettingInitialWindowSize    SettingID = 0x4
+	SettingMaxFrameSize         SettingID = 0x5
+	SettingMaxHeaderListSize    SettingID = 0x6
+)
+
+var settingName = map[SettingID]string{
+	SettingHeaderTableSize:      "HEADER_TABLE_SIZE",
+	SettingEnablePush:           "ENABLE_PUSH",
+	SettingMaxConcurrentStreams: "MAX_CONCURRENT_STREAMS",
+	SettingInitialWindowSize:    "INITIAL_WINDOW_SIZE",
+	SettingMaxFrameSize:         "MAX_FRAME_SIZE",
+	SettingMaxHeaderListSize:    "MAX_HEADER_LIST_SIZE",
+}
+
+func (s SettingID) String() string {
+	if v, ok := settingName[s]; ok {
+		return v
+	}
+	return fmt.Sprintf("UNKNOWN_SETTING_%d", uint16(s))
+}
+
+var (
+	errInvalidHeaderFieldName  = errors.New("http2: invalid header field name")
+	errInvalidHeaderFieldValue = errors.New("http2: invalid header field value")
+)
+
+// validWireHeaderFieldName reports whether v is a valid header field
+// name (key). See httplex.ValidHeaderName for the base rules.
+//
+// Further, http2 says:
+//   "Just as in HTTP/1.x, header field names are strings of ASCII
+//   characters that are compared in a case-insensitive
+//   fashion. However, header field names MUST be converted to
+//   lowercase prior to their encoding in HTTP/2. "
+func validWireHeaderFieldName(v string) bool {
+	if len(v) == 0 {
+		return false
+	}
+	for _, r := range v {
+		if !httplex.IsTokenRune(r) {
+			return false
+		}
+		if 'A' <= r && r <= 'Z' {
+			return false
+		}
+	}
+	return true
+}
+
+var httpCodeStringCommon = map[int]string{} // n -> strconv.Itoa(n)
+
+func init() {
+	for i := 100; i <= 999; i++ {
+		if v := http.StatusText(i); v != "" {
+			httpCodeStringCommon[i] = strconv.Itoa(i)
+		}
+	}
+}
+
+func httpCodeString(code int) string {
+	if s, ok := httpCodeStringCommon[code]; ok {
+		return s
+	}
+	return strconv.Itoa(code)
+}
+
+// from pkg io
+type stringWriter interface {
+	WriteString(s string) (n int, err error)
+}
+
+// A gate lets two goroutines coordinate their activities.
+type gate chan struct{}
+
+func (g gate) Done() { g <- struct{}{} }
+func (g gate) Wait() { <-g }
+
+// A closeWaiter is like a sync.WaitGroup but only goes 1 to 0 (open to closed).
+type closeWaiter chan struct{}
+
+// Init makes a closeWaiter usable.
+// It exists because so a closeWaiter value can be placed inside a
+// larger struct and have the Mutex and Cond's memory in the same
+// allocation.
+func (cw *closeWaiter) Init() {
+	*cw = make(chan struct{})
+}
+
+// Close marks the closeWaiter as closed and unblocks any waiters.
+func (cw closeWaiter) Close() {
+	close(cw)
+}
+
+// Wait waits for the closeWaiter to become closed.
+func (cw closeWaiter) Wait() {
+	<-cw
+}
+
+// bufferedWriter is a buffered writer that writes to w.
+// Its buffered writer is lazily allocated as needed, to minimize
+// idle memory usage with many connections.
+type bufferedWriter struct {
+	w  io.Writer     // immutable
+	bw *bufio.Writer // non-nil when data is buffered
+}
+
+func newBufferedWriter(w io.Writer) *bufferedWriter {
+	return &bufferedWriter{w: w}
+}
+
+var bufWriterPool = sync.Pool{
+	New: func() interface{} {
+		// TODO: pick something better? this is a bit under
+		// (3 x typical 1500 byte MTU) at least.
+		return bufio.NewWriterSize(nil, 4<<10)
+	},
+}
+
+func (w *bufferedWriter) Write(p []byte) (n int, err error) {
+	if w.bw == nil {
+		bw := bufWriterPool.Get().(*bufio.Writer)
+		bw.Reset(w.w)
+		w.bw = bw
+	}
+	return w.bw.Write(p)
+}
+
+func (w *bufferedWriter) Flush() error {
+	bw := w.bw
+	if bw == nil {
+		return nil
+	}
+	err := bw.Flush()
+	bw.Reset(nil)
+	bufWriterPool.Put(bw)
+	w.bw = nil
+	return err
+}
+
+func mustUint31(v int32) uint32 {
+	if v < 0 || v > 2147483647 {
+		panic("out of range")
+	}
+	return uint32(v)
+}
+
+// bodyAllowedForStatus reports whether a given response status code
+// permits a body. See RFC 2616, section 4.4.
+func bodyAllowedForStatus(status int) bool {
+	switch {
+	case status >= 100 && status <= 199:
+		return false
+	case status == 204:
+		return false
+	case status == 304:
+		return false
+	}
+	return true
+}
+
+type httpError struct {
+	msg     string
+	timeout bool
+}
+
+func (e *httpError) Error() string   { return e.msg }
+func (e *httpError) Timeout() bool   { return e.timeout }
+func (e *httpError) Temporary() bool { return true }
+
+var errTimeout error = &httpError{msg: "http2: timeout awaiting response headers", timeout: true}
+
+type connectionStater interface {
+	ConnectionState() tls.ConnectionState
+}
+
+var sorterPool = sync.Pool{New: func() interface{} { return new(sorter) }}
+
+type sorter struct {
+	v []string // owned by sorter
+}
+
+func (s *sorter) Len() int           { return len(s.v) }
+func (s *sorter) Swap(i, j int)      { s.v[i], s.v[j] = s.v[j], s.v[i] }
+func (s *sorter) Less(i, j int) bool { return s.v[i] < s.v[j] }
+
+// Keys returns the sorted keys of h.
+//
+// The returned slice is only valid until s used again or returned to
+// its pool.
+func (s *sorter) Keys(h http.Header) []string {
+	keys := s.v[:0]
+	for k := range h {
+		keys = append(keys, k)
+	}
+	s.v = keys
+	sort.Sort(s)
+	return keys
+}
+
+func (s *sorter) SortStrings(ss []string) {
+	// Our sorter works on s.v, which sorter owners, so
+	// stash it away while we sort the user's buffer.
+	save := s.v
+	s.v = ss
+	sort.Sort(s)
+	s.v = save
+}
diff --git a/vendor/golang.org/x/net/http2/not_go16.go b/vendor/golang.org/x/net/http2/not_go16.go
new file mode 100644
index 0000000..51a7f19
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/not_go16.go
@@ -0,0 +1,20 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.6
+
+package http2
+
+import (
+	"net/http"
+	"time"
+)
+
+func configureTransport(t1 *http.Transport) (*Transport, error) {
+	return nil, errTransportVersion
+}
+
+func transportExpectContinueTimeout(t1 *http.Transport) time.Duration {
+	return 0
+}
diff --git a/vendor/golang.org/x/net/http2/not_go17.go b/vendor/golang.org/x/net/http2/not_go17.go
new file mode 100644
index 0000000..28df0c1
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/not_go17.go
@@ -0,0 +1,51 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.7
+
+package http2
+
+import (
+	"net"
+	"net/http"
+)
+
+type contextContext interface{}
+
+type fakeContext struct{}
+
+func (fakeContext) Done() <-chan struct{} { return nil }
+func (fakeContext) Err() error            { panic("should not be called") }
+
+func reqContext(r *http.Request) fakeContext {
+	return fakeContext{}
+}
+
+func setResponseUncompressed(res *http.Response) {
+	// Nothing.
+}
+
+type clientTrace struct{}
+
+func requestTrace(*http.Request) *clientTrace { return nil }
+func traceGotConn(*http.Request, *ClientConn) {}
+func traceFirstResponseByte(*clientTrace)     {}
+func traceWroteHeaders(*clientTrace)          {}
+func traceWroteRequest(*clientTrace, error)   {}
+func traceGot100Continue(trace *clientTrace)  {}
+func traceWait100Continue(trace *clientTrace) {}
+
+func nop() {}
+
+func serverConnBaseContext(c net.Conn, opts *ServeConnOpts) (ctx contextContext, cancel func()) {
+	return nil, nop
+}
+
+func contextWithCancel(ctx contextContext) (_ contextContext, cancel func()) {
+	return ctx, nop
+}
+
+func requestWithContext(req *http.Request, ctx contextContext) *http.Request {
+	return req
+}
diff --git a/vendor/golang.org/x/net/http2/pipe.go b/vendor/golang.org/x/net/http2/pipe.go
new file mode 100644
index 0000000..69446e7
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/pipe.go
@@ -0,0 +1,147 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http2
+
+import (
+	"errors"
+	"io"
+	"sync"
+)
+
+// pipe is a goroutine-safe io.Reader/io.Writer pair.  It's like
+// io.Pipe except there are no PipeReader/PipeWriter halves, and the
+// underlying buffer is an interface. (io.Pipe is always unbuffered)
+type pipe struct {
+	mu       sync.Mutex
+	c        sync.Cond // c.L lazily initialized to &p.mu
+	b        pipeBuffer
+	err      error         // read error once empty. non-nil means closed.
+	breakErr error         // immediate read error (caller doesn't see rest of b)
+	donec    chan struct{} // closed on error
+	readFn   func()        // optional code to run in Read before error
+}
+
+type pipeBuffer interface {
+	Len() int
+	io.Writer
+	io.Reader
+}
+
+// Read waits until data is available and copies bytes
+// from the buffer into p.
+func (p *pipe) Read(d []byte) (n int, err error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.c.L == nil {
+		p.c.L = &p.mu
+	}
+	for {
+		if p.breakErr != nil {
+			return 0, p.breakErr
+		}
+		if p.b.Len() > 0 {
+			return p.b.Read(d)
+		}
+		if p.err != nil {
+			if p.readFn != nil {
+				p.readFn()     // e.g. copy trailers
+				p.readFn = nil // not sticky like p.err
+			}
+			return 0, p.err
+		}
+		p.c.Wait()
+	}
+}
+
+var errClosedPipeWrite = errors.New("write on closed buffer")
+
+// Write copies bytes from p into the buffer and wakes a reader.
+// It is an error to write more data than the buffer can hold.
+func (p *pipe) Write(d []byte) (n int, err error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.c.L == nil {
+		p.c.L = &p.mu
+	}
+	defer p.c.Signal()
+	if p.err != nil {
+		return 0, errClosedPipeWrite
+	}
+	return p.b.Write(d)
+}
+
+// CloseWithError causes the next Read (waking up a current blocked
+// Read if needed) to return the provided err after all data has been
+// read.
+//
+// The error must be non-nil.
+func (p *pipe) CloseWithError(err error) { p.closeWithError(&p.err, err, nil) }
+
+// BreakWithError causes the next Read (waking up a current blocked
+// Read if needed) to return the provided err immediately, without
+// waiting for unread data.
+func (p *pipe) BreakWithError(err error) { p.closeWithError(&p.breakErr, err, nil) }
+
+// closeWithErrorAndCode is like CloseWithError but also sets some code to run
+// in the caller's goroutine before returning the error.
+func (p *pipe) closeWithErrorAndCode(err error, fn func()) { p.closeWithError(&p.err, err, fn) }
+
+func (p *pipe) closeWithError(dst *error, err error, fn func()) {
+	if err == nil {
+		panic("err must be non-nil")
+	}
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.c.L == nil {
+		p.c.L = &p.mu
+	}
+	defer p.c.Signal()
+	if *dst != nil {
+		// Already been done.
+		return
+	}
+	p.readFn = fn
+	*dst = err
+	p.closeDoneLocked()
+}
+
+// requires p.mu be held.
+func (p *pipe) closeDoneLocked() {
+	if p.donec == nil {
+		return
+	}
+	// Close if unclosed. This isn't racy since we always
+	// hold p.mu while closing.
+	select {
+	case <-p.donec:
+	default:
+		close(p.donec)
+	}
+}
+
+// Err returns the error (if any) first set by BreakWithError or CloseWithError.
+func (p *pipe) Err() error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.breakErr != nil {
+		return p.breakErr
+	}
+	return p.err
+}
+
+// Done returns a channel which is closed if and when this pipe is closed
+// with CloseWithError.
+func (p *pipe) Done() <-chan struct{} {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if p.donec == nil {
+		p.donec = make(chan struct{})
+		if p.err != nil || p.breakErr != nil {
+			// Already hit an error.
+			p.closeDoneLocked()
+		}
+	}
+	return p.donec
+}
diff --git a/vendor/golang.org/x/net/http2/server.go b/vendor/golang.org/x/net/http2/server.go
new file mode 100644
index 0000000..1de8146
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/server.go
@@ -0,0 +1,2287 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// TODO: replace all <-sc.doneServing with reads from the stream's cw
+// instead, and make sure that on close we close all open
+// streams. then remove doneServing?
+
+// TODO: re-audit GOAWAY support. Consider each incoming frame type and
+// whether it should be ignored during graceful shutdown.
+
+// TODO: disconnect idle clients. GFE seems to do 4 minutes. make
+// configurable?  or maximum number of idle clients and remove the
+// oldest?
+
+// TODO: turn off the serve goroutine when idle, so
+// an idle conn only has the readFrames goroutine active. (which could
+// also be optimized probably to pin less memory in crypto/tls). This
+// would involve tracking when the serve goroutine is active (atomic
+// int32 read/CAS probably?) and starting it up when frames arrive,
+// and shutting it down when all handlers exit. the occasional PING
+// packets could use time.AfterFunc to call sc.wakeStartServeLoop()
+// (which is a no-op if already running) and then queue the PING write
+// as normal. The serve loop would then exit in most cases (if no
+// Handlers running) and not be woken up again until the PING packet
+// returns.
+
+// TODO (maybe): add a mechanism for Handlers to going into
+// half-closed-local mode (rw.(io.Closer) test?) but not exit their
+// handler, and continue to be able to read from the
+// Request.Body. This would be a somewhat semantic change from HTTP/1
+// (or at least what we expose in net/http), so I'd probably want to
+// add it there too. For now, this package says that returning from
+// the Handler ServeHTTP function means you're both done reading and
+// done writing, without a way to stop just one or the other.
+
+package http2
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"net/textproto"
+	"net/url"
+	"os"
+	"reflect"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/net/http2/hpack"
+)
+
+const (
+	prefaceTimeout        = 10 * time.Second
+	firstSettingsTimeout  = 2 * time.Second // should be in-flight with preface anyway
+	handlerChunkWriteSize = 4 << 10
+	defaultMaxStreams     = 250 // TODO: make this 100 as the GFE seems to?
+)
+
+var (
+	errClientDisconnected = errors.New("client disconnected")
+	errClosedBody         = errors.New("body closed by handler")
+	errHandlerComplete    = errors.New("http2: request body closed due to handler exiting")
+	errStreamClosed       = errors.New("http2: stream closed")
+)
+
+var responseWriterStatePool = sync.Pool{
+	New: func() interface{} {
+		rws := &responseWriterState{}
+		rws.bw = bufio.NewWriterSize(chunkWriter{rws}, handlerChunkWriteSize)
+		return rws
+	},
+}
+
+// Test hooks.
+var (
+	testHookOnConn        func()
+	testHookGetServerConn func(*serverConn)
+	testHookOnPanicMu     *sync.Mutex // nil except in tests
+	testHookOnPanic       func(sc *serverConn, panicVal interface{}) (rePanic bool)
+)
+
+// Server is an HTTP/2 server.
+type Server struct {
+	// MaxHandlers limits the number of http.Handler ServeHTTP goroutines
+	// which may run at a time over all connections.
+	// Negative or zero no limit.
+	// TODO: implement
+	MaxHandlers int
+
+	// MaxConcurrentStreams optionally specifies the number of
+	// concurrent streams that each client may have open at a
+	// time. This is unrelated to the number of http.Handler goroutines
+	// which may be active globally, which is MaxHandlers.
+	// If zero, MaxConcurrentStreams defaults to at least 100, per
+	// the HTTP/2 spec's recommendations.
+	MaxConcurrentStreams uint32
+
+	// MaxReadFrameSize optionally specifies the largest frame
+	// this server is willing to read. A valid value is between
+	// 16k and 16M, inclusive. If zero or otherwise invalid, a
+	// default value is used.
+	MaxReadFrameSize uint32
+
+	// PermitProhibitedCipherSuites, if true, permits the use of
+	// cipher suites prohibited by the HTTP/2 spec.
+	PermitProhibitedCipherSuites bool
+}
+
+func (s *Server) maxReadFrameSize() uint32 {
+	if v := s.MaxReadFrameSize; v >= minMaxFrameSize && v <= maxFrameSize {
+		return v
+	}
+	return defaultMaxReadFrameSize
+}
+
+func (s *Server) maxConcurrentStreams() uint32 {
+	if v := s.MaxConcurrentStreams; v > 0 {
+		return v
+	}
+	return defaultMaxStreams
+}
+
+// ConfigureServer adds HTTP/2 support to a net/http Server.
+//
+// The configuration conf may be nil.
+//
+// ConfigureServer must be called before s begins serving.
+func ConfigureServer(s *http.Server, conf *Server) error {
+	if conf == nil {
+		conf = new(Server)
+	}
+
+	if s.TLSConfig == nil {
+		s.TLSConfig = new(tls.Config)
+	} else if s.TLSConfig.CipherSuites != nil {
+		// If they already provided a CipherSuite list, return
+		// an error if it has a bad order or is missing
+		// ECDHE_RSA_WITH_AES_128_GCM_SHA256.
+		const requiredCipher = tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
+		haveRequired := false
+		sawBad := false
+		for i, cs := range s.TLSConfig.CipherSuites {
+			if cs == requiredCipher {
+				haveRequired = true
+			}
+			if isBadCipher(cs) {
+				sawBad = true
+			} else if sawBad {
+				return fmt.Errorf("http2: TLSConfig.CipherSuites index %d contains an HTTP/2-approved cipher suite (%#04x), but it comes after unapproved cipher suites. With this configuration, clients that don't support previous, approved cipher suites may be given an unapproved one and reject the connection.", i, cs)
+			}
+		}
+		if !haveRequired {
+			return fmt.Errorf("http2: TLSConfig.CipherSuites is missing HTTP/2-required TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256")
+		}
+	}
+
+	// Note: not setting MinVersion to tls.VersionTLS12,
+	// as we don't want to interfere with HTTP/1.1 traffic
+	// on the user's server. We enforce TLS 1.2 later once
+	// we accept a connection. Ideally this should be done
+	// during next-proto selection, but using TLS <1.2 with
+	// HTTP/2 is still the client's bug.
+
+	s.TLSConfig.PreferServerCipherSuites = true
+
+	haveNPN := false
+	for _, p := range s.TLSConfig.NextProtos {
+		if p == NextProtoTLS {
+			haveNPN = true
+			break
+		}
+	}
+	if !haveNPN {
+		s.TLSConfig.NextProtos = append(s.TLSConfig.NextProtos, NextProtoTLS)
+	}
+	// h2-14 is temporary (as of 2015-03-05) while we wait for all browsers
+	// to switch to "h2".
+	s.TLSConfig.NextProtos = append(s.TLSConfig.NextProtos, "h2-14")
+
+	if s.TLSNextProto == nil {
+		s.TLSNextProto = map[string]func(*http.Server, *tls.Conn, http.Handler){}
+	}
+	protoHandler := func(hs *http.Server, c *tls.Conn, h http.Handler) {
+		if testHookOnConn != nil {
+			testHookOnConn()
+		}
+		conf.ServeConn(c, &ServeConnOpts{
+			Handler:    h,
+			BaseConfig: hs,
+		})
+	}
+	s.TLSNextProto[NextProtoTLS] = protoHandler
+	s.TLSNextProto["h2-14"] = protoHandler // temporary; see above.
+	return nil
+}
+
+// ServeConnOpts are options for the Server.ServeConn method.
+type ServeConnOpts struct {
+	// BaseConfig optionally sets the base configuration
+	// for values. If nil, defaults are used.
+	BaseConfig *http.Server
+
+	// Handler specifies which handler to use for processing
+	// requests. If nil, BaseConfig.Handler is used. If BaseConfig
+	// or BaseConfig.Handler is nil, http.DefaultServeMux is used.
+	Handler http.Handler
+}
+
+func (o *ServeConnOpts) baseConfig() *http.Server {
+	if o != nil && o.BaseConfig != nil {
+		return o.BaseConfig
+	}
+	return new(http.Server)
+}
+
+func (o *ServeConnOpts) handler() http.Handler {
+	if o != nil {
+		if o.Handler != nil {
+			return o.Handler
+		}
+		if o.BaseConfig != nil && o.BaseConfig.Handler != nil {
+			return o.BaseConfig.Handler
+		}
+	}
+	return http.DefaultServeMux
+}
+
+// ServeConn serves HTTP/2 requests on the provided connection and
+// blocks until the connection is no longer readable.
+//
+// ServeConn starts speaking HTTP/2 assuming that c has not had any
+// reads or writes. It writes its initial settings frame and expects
+// to be able to read the preface and settings frame from the
+// client. If c has a ConnectionState method like a *tls.Conn, the
+// ConnectionState is used to verify the TLS ciphersuite and to set
+// the Request.TLS field in Handlers.
+//
+// ServeConn does not support h2c by itself. Any h2c support must be
+// implemented in terms of providing a suitably-behaving net.Conn.
+//
+// The opts parameter is optional. If nil, default values are used.
+func (s *Server) ServeConn(c net.Conn, opts *ServeConnOpts) {
+	baseCtx, cancel := serverConnBaseContext(c, opts)
+	defer cancel()
+
+	sc := &serverConn{
+		srv:              s,
+		hs:               opts.baseConfig(),
+		conn:             c,
+		baseCtx:          baseCtx,
+		remoteAddrStr:    c.RemoteAddr().String(),
+		bw:               newBufferedWriter(c),
+		handler:          opts.handler(),
+		streams:          make(map[uint32]*stream),
+		readFrameCh:      make(chan readFrameResult),
+		wantWriteFrameCh: make(chan frameWriteMsg, 8),
+		wroteFrameCh:     make(chan frameWriteResult, 1), // buffered; one send in writeFrameAsync
+		bodyReadCh:       make(chan bodyReadMsg),         // buffering doesn't matter either way
+		doneServing:      make(chan struct{}),
+		advMaxStreams:    s.maxConcurrentStreams(),
+		writeSched: writeScheduler{
+			maxFrameSize: initialMaxFrameSize,
+		},
+		initialWindowSize: initialWindowSize,
+		headerTableSize:   initialHeaderTableSize,
+		serveG:            newGoroutineLock(),
+		pushEnabled:       true,
+	}
+
+	sc.flow.add(initialWindowSize)
+	sc.inflow.add(initialWindowSize)
+	sc.hpackEncoder = hpack.NewEncoder(&sc.headerWriteBuf)
+
+	fr := NewFramer(sc.bw, c)
+	fr.ReadMetaHeaders = hpack.NewDecoder(initialHeaderTableSize, nil)
+	fr.MaxHeaderListSize = sc.maxHeaderListSize()
+	fr.SetMaxReadFrameSize(s.maxReadFrameSize())
+	sc.framer = fr
+
+	if tc, ok := c.(connectionStater); ok {
+		sc.tlsState = new(tls.ConnectionState)
+		*sc.tlsState = tc.ConnectionState()
+		// 9.2 Use of TLS Features
+		// An implementation of HTTP/2 over TLS MUST use TLS
+		// 1.2 or higher with the restrictions on feature set
+		// and cipher suite described in this section. Due to
+		// implementation limitations, it might not be
+		// possible to fail TLS negotiation. An endpoint MUST
+		// immediately terminate an HTTP/2 connection that
+		// does not meet the TLS requirements described in
+		// this section with a connection error (Section
+		// 5.4.1) of type INADEQUATE_SECURITY.
+		if sc.tlsState.Version < tls.VersionTLS12 {
+			sc.rejectConn(ErrCodeInadequateSecurity, "TLS version too low")
+			return
+		}
+
+		if sc.tlsState.ServerName == "" {
+			// Client must use SNI, but we don't enforce that anymore,
+			// since it was causing problems when connecting to bare IP
+			// addresses during development.
+			//
+			// TODO: optionally enforce? Or enforce at the time we receive
+			// a new request, and verify the the ServerName matches the :authority?
+			// But that precludes proxy situations, perhaps.
+			//
+			// So for now, do nothing here again.
+		}
+
+		if !s.PermitProhibitedCipherSuites && isBadCipher(sc.tlsState.CipherSuite) {
+			// "Endpoints MAY choose to generate a connection error
+			// (Section 5.4.1) of type INADEQUATE_SECURITY if one of
+			// the prohibited cipher suites are negotiated."
+			//
+			// We choose that. In my opinion, the spec is weak
+			// here. It also says both parties must support at least
+			// TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 so there's no
+			// excuses here. If we really must, we could allow an
+			// "AllowInsecureWeakCiphers" option on the server later.
+			// Let's see how it plays out first.
+			sc.rejectConn(ErrCodeInadequateSecurity, fmt.Sprintf("Prohibited TLS 1.2 Cipher Suite: %x", sc.tlsState.CipherSuite))
+			return
+		}
+	}
+
+	if hook := testHookGetServerConn; hook != nil {
+		hook(sc)
+	}
+	sc.serve()
+}
+
+// isBadCipher reports whether the cipher is blacklisted by the HTTP/2 spec.
+func isBadCipher(cipher uint16) bool {
+	switch cipher {
+	case tls.TLS_RSA_WITH_RC4_128_SHA,
+		tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
+		tls.TLS_RSA_WITH_AES_128_CBC_SHA,
+		tls.TLS_RSA_WITH_AES_256_CBC_SHA,
+		tls.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
+		tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
+		tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+		tls.TLS_ECDHE_RSA_WITH_RC4_128_SHA,
+		tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
+		tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+		tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA:
+		// Reject cipher suites from Appendix A.
+		// "This list includes those cipher suites that do not
+		// offer an ephemeral key exchange and those that are
+		// based on the TLS null, stream or block cipher type"
+		return true
+	default:
+		return false
+	}
+}
+
+func (sc *serverConn) rejectConn(err ErrCode, debug string) {
+	sc.vlogf("http2: server rejecting conn: %v, %s", err, debug)
+	// ignoring errors. hanging up anyway.
+	sc.framer.WriteGoAway(0, err, []byte(debug))
+	sc.bw.Flush()
+	sc.conn.Close()
+}
+
+type serverConn struct {
+	// Immutable:
+	srv              *Server
+	hs               *http.Server
+	conn             net.Conn
+	bw               *bufferedWriter // writing to conn
+	handler          http.Handler
+	baseCtx          contextContext
+	framer           *Framer
+	doneServing      chan struct{}         // closed when serverConn.serve ends
+	readFrameCh      chan readFrameResult  // written by serverConn.readFrames
+	wantWriteFrameCh chan frameWriteMsg    // from handlers -> serve
+	wroteFrameCh     chan frameWriteResult // from writeFrameAsync -> serve, tickles more frame writes
+	bodyReadCh       chan bodyReadMsg      // from handlers -> serve
+	testHookCh       chan func(int)        // code to run on the serve loop
+	flow             flow                  // conn-wide (not stream-specific) outbound flow control
+	inflow           flow                  // conn-wide inbound flow control
+	tlsState         *tls.ConnectionState  // shared by all handlers, like net/http
+	remoteAddrStr    string
+
+	// Everything following is owned by the serve loop; use serveG.check():
+	serveG                goroutineLock // used to verify funcs are on serve()
+	pushEnabled           bool
+	sawFirstSettings      bool // got the initial SETTINGS frame after the preface
+	needToSendSettingsAck bool
+	unackedSettings       int    // how many SETTINGS have we sent without ACKs?
+	clientMaxStreams      uint32 // SETTINGS_MAX_CONCURRENT_STREAMS from client (our PUSH_PROMISE limit)
+	advMaxStreams         uint32 // our SETTINGS_MAX_CONCURRENT_STREAMS advertised the client
+	curOpenStreams        uint32 // client's number of open streams
+	maxStreamID           uint32 // max ever seen
+	streams               map[uint32]*stream
+	initialWindowSize     int32
+	headerTableSize       uint32
+	peerMaxHeaderListSize uint32            // zero means unknown (default)
+	canonHeader           map[string]string // http2-lower-case -> Go-Canonical-Case
+	writingFrame          bool              // started write goroutine but haven't heard back on wroteFrameCh
+	needsFrameFlush       bool              // last frame write wasn't a flush
+	writeSched            writeScheduler
+	inGoAway              bool // we've started to or sent GOAWAY
+	needToSendGoAway      bool // we need to schedule a GOAWAY frame write
+	goAwayCode            ErrCode
+	shutdownTimerCh       <-chan time.Time // nil until used
+	shutdownTimer         *time.Timer      // nil until used
+	freeRequestBodyBuf    []byte           // if non-nil, a free initialWindowSize buffer for getRequestBodyBuf
+
+	// Owned by the writeFrameAsync goroutine:
+	headerWriteBuf bytes.Buffer
+	hpackEncoder   *hpack.Encoder
+}
+
+func (sc *serverConn) maxHeaderListSize() uint32 {
+	n := sc.hs.MaxHeaderBytes
+	if n <= 0 {
+		n = http.DefaultMaxHeaderBytes
+	}
+	// http2's count is in a slightly different unit and includes 32 bytes per pair.
+	// So, take the net/http.Server value and pad it up a bit, assuming 10 headers.
+	const perFieldOverhead = 32 // per http2 spec
+	const typicalHeaders = 10   // conservative
+	return uint32(n + typicalHeaders*perFieldOverhead)
+}
+
+// stream represents a stream. This is the minimal metadata needed by
+// the serve goroutine. Most of the actual stream state is owned by
+// the http.Handler's goroutine in the responseWriter. Because the
+// responseWriter's responseWriterState is recycled at the end of a
+// handler, this struct intentionally has no pointer to the
+// *responseWriter{,State} itself, as the Handler ending nils out the
+// responseWriter's state field.
+type stream struct {
+	// immutable:
+	sc        *serverConn
+	id        uint32
+	body      *pipe       // non-nil if expecting DATA frames
+	cw        closeWaiter // closed wait stream transitions to closed state
+	ctx       contextContext
+	cancelCtx func()
+
+	// owned by serverConn's serve loop:
+	bodyBytes        int64   // body bytes seen so far
+	declBodyBytes    int64   // or -1 if undeclared
+	flow             flow    // limits writing from Handler to client
+	inflow           flow    // what the client is allowed to POST/etc to us
+	parent           *stream // or nil
+	numTrailerValues int64
+	weight           uint8
+	state            streamState
+	sentReset        bool // only true once detached from streams map
+	gotReset         bool // only true once detacted from streams map
+	gotTrailerHeader bool // HEADER frame for trailers was seen
+	wroteHeaders     bool // whether we wrote headers (not status 100)
+	reqBuf           []byte
+
+	trailer    http.Header // accumulated trailers
+	reqTrailer http.Header // handler's Request.Trailer
+}
+
+func (sc *serverConn) Framer() *Framer  { return sc.framer }
+func (sc *serverConn) CloseConn() error { return sc.conn.Close() }
+func (sc *serverConn) Flush() error     { return sc.bw.Flush() }
+func (sc *serverConn) HeaderEncoder() (*hpack.Encoder, *bytes.Buffer) {
+	return sc.hpackEncoder, &sc.headerWriteBuf
+}
+
+func (sc *serverConn) state(streamID uint32) (streamState, *stream) {
+	sc.serveG.check()
+	// http://http2.github.io/http2-spec/#rfc.section.5.1
+	if st, ok := sc.streams[streamID]; ok {
+		return st.state, st
+	}
+	// "The first use of a new stream identifier implicitly closes all
+	// streams in the "idle" state that might have been initiated by
+	// that peer with a lower-valued stream identifier. For example, if
+	// a client sends a HEADERS frame on stream 7 without ever sending a
+	// frame on stream 5, then stream 5 transitions to the "closed"
+	// state when the first frame for stream 7 is sent or received."
+	if streamID <= sc.maxStreamID {
+		return stateClosed, nil
+	}
+	return stateIdle, nil
+}
+
+// setConnState calls the net/http ConnState hook for this connection, if configured.
+// Note that the net/http package does StateNew and StateClosed for us.
+// There is currently no plan for StateHijacked or hijacking HTTP/2 connections.
+func (sc *serverConn) setConnState(state http.ConnState) {
+	if sc.hs.ConnState != nil {
+		sc.hs.ConnState(sc.conn, state)
+	}
+}
+
+func (sc *serverConn) vlogf(format string, args ...interface{}) {
+	if VerboseLogs {
+		sc.logf(format, args...)
+	}
+}
+
+func (sc *serverConn) logf(format string, args ...interface{}) {
+	if lg := sc.hs.ErrorLog; lg != nil {
+		lg.Printf(format, args...)
+	} else {
+		log.Printf(format, args...)
+	}
+}
+
+// errno returns v's underlying uintptr, else 0.
+//
+// TODO: remove this helper function once http2 can use build
+// tags. See comment in isClosedConnError.
+func errno(v error) uintptr {
+	if rv := reflect.ValueOf(v); rv.Kind() == reflect.Uintptr {
+		return uintptr(rv.Uint())
+	}
+	return 0
+}
+
+// isClosedConnError reports whether err is an error from use of a closed
+// network connection.
+func isClosedConnError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	// TODO: remove this string search and be more like the Windows
+	// case below. That might involve modifying the standard library
+	// to return better error types.
+	str := err.Error()
+	if strings.Contains(str, "use of closed network connection") {
+		return true
+	}
+
+	// TODO(bradfitz): x/tools/cmd/bundle doesn't really support
+	// build tags, so I can't make an http2_windows.go file with
+	// Windows-specific stuff. Fix that and move this, once we
+	// have a way to bundle this into std's net/http somehow.
+	if runtime.GOOS == "windows" {
+		if oe, ok := err.(*net.OpError); ok && oe.Op == "read" {
+			if se, ok := oe.Err.(*os.SyscallError); ok && se.Syscall == "wsarecv" {
+				const WSAECONNABORTED = 10053
+				const WSAECONNRESET = 10054
+				if n := errno(se.Err); n == WSAECONNRESET || n == WSAECONNABORTED {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}
+
+func (sc *serverConn) condlogf(err error, format string, args ...interface{}) {
+	if err == nil {
+		return
+	}
+	if err == io.EOF || err == io.ErrUnexpectedEOF || isClosedConnError(err) {
+		// Boring, expected errors.
+		sc.vlogf(format, args...)
+	} else {
+		sc.logf(format, args...)
+	}
+}
+
+func (sc *serverConn) canonicalHeader(v string) string {
+	sc.serveG.check()
+	cv, ok := commonCanonHeader[v]
+	if ok {
+		return cv
+	}
+	cv, ok = sc.canonHeader[v]
+	if ok {
+		return cv
+	}
+	if sc.canonHeader == nil {
+		sc.canonHeader = make(map[string]string)
+	}
+	cv = http.CanonicalHeaderKey(v)
+	sc.canonHeader[v] = cv
+	return cv
+}
+
+type readFrameResult struct {
+	f   Frame // valid until readMore is called
+	err error
+
+	// readMore should be called once the consumer no longer needs or
+	// retains f. After readMore, f is invalid and more frames can be
+	// read.
+	readMore func()
+}
+
+// readFrames is the loop that reads incoming frames.
+// It takes care to only read one frame at a time, blocking until the
+// consumer is done with the frame.
+// It's run on its own goroutine.
+func (sc *serverConn) readFrames() {
+	gate := make(gate)
+	gateDone := gate.Done
+	for {
+		f, err := sc.framer.ReadFrame()
+		select {
+		case sc.readFrameCh <- readFrameResult{f, err, gateDone}:
+		case <-sc.doneServing:
+			return
+		}
+		select {
+		case <-gate:
+		case <-sc.doneServing:
+			return
+		}
+		if terminalReadFrameError(err) {
+			return
+		}
+	}
+}
+
+// frameWriteResult is the message passed from writeFrameAsync to the serve goroutine.
+type frameWriteResult struct {
+	wm  frameWriteMsg // what was written (or attempted)
+	err error         // result of the writeFrame call
+}
+
+// writeFrameAsync runs in its own goroutine and writes a single frame
+// and then reports when it's done.
+// At most one goroutine can be running writeFrameAsync at a time per
+// serverConn.
+func (sc *serverConn) writeFrameAsync(wm frameWriteMsg) {
+	err := wm.write.writeFrame(sc)
+	sc.wroteFrameCh <- frameWriteResult{wm, err}
+}
+
+func (sc *serverConn) closeAllStreamsOnConnClose() {
+	sc.serveG.check()
+	for _, st := range sc.streams {
+		sc.closeStream(st, errClientDisconnected)
+	}
+}
+
+func (sc *serverConn) stopShutdownTimer() {
+	sc.serveG.check()
+	if t := sc.shutdownTimer; t != nil {
+		t.Stop()
+	}
+}
+
+func (sc *serverConn) notePanic() {
+	// Note: this is for serverConn.serve panicking, not http.Handler code.
+	if testHookOnPanicMu != nil {
+		testHookOnPanicMu.Lock()
+		defer testHookOnPanicMu.Unlock()
+	}
+	if testHookOnPanic != nil {
+		if e := recover(); e != nil {
+			if testHookOnPanic(sc, e) {
+				panic(e)
+			}
+		}
+	}
+}
+
+func (sc *serverConn) serve() {
+	sc.serveG.check()
+	defer sc.notePanic()
+	defer sc.conn.Close()
+	defer sc.closeAllStreamsOnConnClose()
+	defer sc.stopShutdownTimer()
+	defer close(sc.doneServing) // unblocks handlers trying to send
+
+	if VerboseLogs {
+		sc.vlogf("http2: server connection from %v on %p", sc.conn.RemoteAddr(), sc.hs)
+	}
+
+	sc.writeFrame(frameWriteMsg{
+		write: writeSettings{
+			{SettingMaxFrameSize, sc.srv.maxReadFrameSize()},
+			{SettingMaxConcurrentStreams, sc.advMaxStreams},
+			{SettingMaxHeaderListSize, sc.maxHeaderListSize()},
+
+			// TODO: more actual settings, notably
+			// SettingInitialWindowSize, but then we also
+			// want to bump up the conn window size the
+			// same amount here right after the settings
+		},
+	})
+	sc.unackedSettings++
+
+	if err := sc.readPreface(); err != nil {
+		sc.condlogf(err, "http2: server: error reading preface from client %v: %v", sc.conn.RemoteAddr(), err)
+		return
+	}
+	// Now that we've got the preface, get us out of the
+	// "StateNew" state.  We can't go directly to idle, though.
+	// Active means we read some data and anticipate a request. We'll
+	// do another Active when we get a HEADERS frame.
+	sc.setConnState(http.StateActive)
+	sc.setConnState(http.StateIdle)
+
+	go sc.readFrames() // closed by defer sc.conn.Close above
+
+	settingsTimer := time.NewTimer(firstSettingsTimeout)
+	loopNum := 0
+	for {
+		loopNum++
+		select {
+		case wm := <-sc.wantWriteFrameCh:
+			sc.writeFrame(wm)
+		case res := <-sc.wroteFrameCh:
+			sc.wroteFrame(res)
+		case res := <-sc.readFrameCh:
+			if !sc.processFrameFromReader(res) {
+				return
+			}
+			res.readMore()
+			if settingsTimer.C != nil {
+				settingsTimer.Stop()
+				settingsTimer.C = nil
+			}
+		case m := <-sc.bodyReadCh:
+			sc.noteBodyRead(m.st, m.n)
+		case <-settingsTimer.C:
+			sc.logf("timeout waiting for SETTINGS frames from %v", sc.conn.RemoteAddr())
+			return
+		case <-sc.shutdownTimerCh:
+			sc.vlogf("GOAWAY close timer fired; closing conn from %v", sc.conn.RemoteAddr())
+			return
+		case fn := <-sc.testHookCh:
+			fn(loopNum)
+		}
+	}
+}
+
+// readPreface reads the ClientPreface greeting from the peer
+// or returns an error on timeout or an invalid greeting.
+func (sc *serverConn) readPreface() error {
+	errc := make(chan error, 1)
+	go func() {
+		// Read the client preface
+		buf := make([]byte, len(ClientPreface))
+		if _, err := io.ReadFull(sc.conn, buf); err != nil {
+			errc <- err
+		} else if !bytes.Equal(buf, clientPreface) {
+			errc <- fmt.Errorf("bogus greeting %q", buf)
+		} else {
+			errc <- nil
+		}
+	}()
+	timer := time.NewTimer(prefaceTimeout) // TODO: configurable on *Server?
+	defer timer.Stop()
+	select {
+	case <-timer.C:
+		return errors.New("timeout waiting for client preface")
+	case err := <-errc:
+		if err == nil {
+			if VerboseLogs {
+				sc.vlogf("http2: server: client %v said hello", sc.conn.RemoteAddr())
+			}
+		}
+		return err
+	}
+}
+
+var errChanPool = sync.Pool{
+	New: func() interface{} { return make(chan error, 1) },
+}
+
+var writeDataPool = sync.Pool{
+	New: func() interface{} { return new(writeData) },
+}
+
+// writeDataFromHandler writes DATA response frames from a handler on
+// the given stream.
+func (sc *serverConn) writeDataFromHandler(stream *stream, data []byte, endStream bool) error {
+	ch := errChanPool.Get().(chan error)
+	writeArg := writeDataPool.Get().(*writeData)
+	*writeArg = writeData{stream.id, data, endStream}
+	err := sc.writeFrameFromHandler(frameWriteMsg{
+		write:  writeArg,
+		stream: stream,
+		done:   ch,
+	})
+	if err != nil {
+		return err
+	}
+	var frameWriteDone bool // the frame write is done (successfully or not)
+	select {
+	case err = <-ch:
+		frameWriteDone = true
+	case <-sc.doneServing:
+		return errClientDisconnected
+	case <-stream.cw:
+		// If both ch and stream.cw were ready (as might
+		// happen on the final Write after an http.Handler
+		// ends), prefer the write result. Otherwise this
+		// might just be us successfully closing the stream.
+		// The writeFrameAsync and serve goroutines guarantee
+		// that the ch send will happen before the stream.cw
+		// close.
+		select {
+		case err = <-ch:
+			frameWriteDone = true
+		default:
+			return errStreamClosed
+		}
+	}
+	errChanPool.Put(ch)
+	if frameWriteDone {
+		writeDataPool.Put(writeArg)
+	}
+	return err
+}
+
+// writeFrameFromHandler sends wm to sc.wantWriteFrameCh, but aborts
+// if the connection has gone away.
+//
+// This must not be run from the serve goroutine itself, else it might
+// deadlock writing to sc.wantWriteFrameCh (which is only mildly
+// buffered and is read by serve itself). If you're on the serve
+// goroutine, call writeFrame instead.
+func (sc *serverConn) writeFrameFromHandler(wm frameWriteMsg) error {
+	sc.serveG.checkNotOn() // NOT
+	select {
+	case sc.wantWriteFrameCh <- wm:
+		return nil
+	case <-sc.doneServing:
+		// Serve loop is gone.
+		// Client has closed their connection to the server.
+		return errClientDisconnected
+	}
+}
+
+// writeFrame schedules a frame to write and sends it if there's nothing
+// already being written.
+//
+// There is no pushback here (the serve goroutine never blocks). It's
+// the http.Handlers that block, waiting for their previous frames to
+// make it onto the wire
+//
+// If you're not on the serve goroutine, use writeFrameFromHandler instead.
+func (sc *serverConn) writeFrame(wm frameWriteMsg) {
+	sc.serveG.check()
+
+	var ignoreWrite bool
+
+	// Don't send a 100-continue response if we've already sent headers.
+	// See golang.org/issue/14030.
+	switch wm.write.(type) {
+	case *writeResHeaders:
+		wm.stream.wroteHeaders = true
+	case write100ContinueHeadersFrame:
+		if wm.stream.wroteHeaders {
+			ignoreWrite = true
+		}
+	}
+
+	if !ignoreWrite {
+		sc.writeSched.add(wm)
+	}
+	sc.scheduleFrameWrite()
+}
+
+// startFrameWrite starts a goroutine to write wm (in a separate
+// goroutine since that might block on the network), and updates the
+// serve goroutine's state about the world, updated from info in wm.
+func (sc *serverConn) startFrameWrite(wm frameWriteMsg) {
+	sc.serveG.check()
+	if sc.writingFrame {
+		panic("internal error: can only be writing one frame at a time")
+	}
+
+	st := wm.stream
+	if st != nil {
+		switch st.state {
+		case stateHalfClosedLocal:
+			panic("internal error: attempt to send frame on half-closed-local stream")
+		case stateClosed:
+			if st.sentReset || st.gotReset {
+				// Skip this frame.
+				sc.scheduleFrameWrite()
+				return
+			}
+			panic(fmt.Sprintf("internal error: attempt to send a write %v on a closed stream", wm))
+		}
+	}
+
+	sc.writingFrame = true
+	sc.needsFrameFlush = true
+	go sc.writeFrameAsync(wm)
+}
+
+// errHandlerPanicked is the error given to any callers blocked in a read from
+// Request.Body when the main goroutine panics. Since most handlers read in the
+// the main ServeHTTP goroutine, this will show up rarely.
+var errHandlerPanicked = errors.New("http2: handler panicked")
+
+// wroteFrame is called on the serve goroutine with the result of
+// whatever happened on writeFrameAsync.
+func (sc *serverConn) wroteFrame(res frameWriteResult) {
+	sc.serveG.check()
+	if !sc.writingFrame {
+		panic("internal error: expected to be already writing a frame")
+	}
+	sc.writingFrame = false
+
+	wm := res.wm
+	st := wm.stream
+
+	closeStream := endsStream(wm.write)
+
+	if _, ok := wm.write.(handlerPanicRST); ok {
+		sc.closeStream(st, errHandlerPanicked)
+	}
+
+	// Reply (if requested) to the blocked ServeHTTP goroutine.
+	if ch := wm.done; ch != nil {
+		select {
+		case ch <- res.err:
+		default:
+			panic(fmt.Sprintf("unbuffered done channel passed in for type %T", wm.write))
+		}
+	}
+	wm.write = nil // prevent use (assume it's tainted after wm.done send)
+
+	if closeStream {
+		if st == nil {
+			panic("internal error: expecting non-nil stream")
+		}
+		switch st.state {
+		case stateOpen:
+			// Here we would go to stateHalfClosedLocal in
+			// theory, but since our handler is done and
+			// the net/http package provides no mechanism
+			// for finishing writing to a ResponseWriter
+			// while still reading data (see possible TODO
+			// at top of this file), we go into closed
+			// state here anyway, after telling the peer
+			// we're hanging up on them.
+			st.state = stateHalfClosedLocal // won't last long, but necessary for closeStream via resetStream
+			errCancel := StreamError{st.id, ErrCodeCancel}
+			sc.resetStream(errCancel)
+		case stateHalfClosedRemote:
+			sc.closeStream(st, errHandlerComplete)
+		}
+	}
+
+	sc.scheduleFrameWrite()
+}
+
+// scheduleFrameWrite tickles the frame writing scheduler.
+//
+// If a frame is already being written, nothing happens. This will be called again
+// when the frame is done being written.
+//
+// If a frame isn't being written we need to send one, the best frame
+// to send is selected, preferring first things that aren't
+// stream-specific (e.g. ACKing settings), and then finding the
+// highest priority stream.
+//
+// If a frame isn't being written and there's nothing else to send, we
+// flush the write buffer.
+func (sc *serverConn) scheduleFrameWrite() {
+	sc.serveG.check()
+	if sc.writingFrame {
+		return
+	}
+	if sc.needToSendGoAway {
+		sc.needToSendGoAway = false
+		sc.startFrameWrite(frameWriteMsg{
+			write: &writeGoAway{
+				maxStreamID: sc.maxStreamID,
+				code:        sc.goAwayCode,
+			},
+		})
+		return
+	}
+	if sc.needToSendSettingsAck {
+		sc.needToSendSettingsAck = false
+		sc.startFrameWrite(frameWriteMsg{write: writeSettingsAck{}})
+		return
+	}
+	if !sc.inGoAway {
+		if wm, ok := sc.writeSched.take(); ok {
+			sc.startFrameWrite(wm)
+			return
+		}
+	}
+	if sc.needsFrameFlush {
+		sc.startFrameWrite(frameWriteMsg{write: flushFrameWriter{}})
+		sc.needsFrameFlush = false // after startFrameWrite, since it sets this true
+		return
+	}
+}
+
+func (sc *serverConn) goAway(code ErrCode) {
+	sc.serveG.check()
+	if sc.inGoAway {
+		return
+	}
+	if code != ErrCodeNo {
+		sc.shutDownIn(250 * time.Millisecond)
+	} else {
+		// TODO: configurable
+		sc.shutDownIn(1 * time.Second)
+	}
+	sc.inGoAway = true
+	sc.needToSendGoAway = true
+	sc.goAwayCode = code
+	sc.scheduleFrameWrite()
+}
+
+func (sc *serverConn) shutDownIn(d time.Duration) {
+	sc.serveG.check()
+	sc.shutdownTimer = time.NewTimer(d)
+	sc.shutdownTimerCh = sc.shutdownTimer.C
+}
+
+func (sc *serverConn) resetStream(se StreamError) {
+	sc.serveG.check()
+	sc.writeFrame(frameWriteMsg{write: se})
+	if st, ok := sc.streams[se.StreamID]; ok {
+		st.sentReset = true
+		sc.closeStream(st, se)
+	}
+}
+
+// processFrameFromReader processes the serve loop's read from readFrameCh from the
+// frame-reading goroutine.
+// processFrameFromReader returns whether the connection should be kept open.
+func (sc *serverConn) processFrameFromReader(res readFrameResult) bool {
+	sc.serveG.check()
+	err := res.err
+	if err != nil {
+		if err == ErrFrameTooLarge {
+			sc.goAway(ErrCodeFrameSize)
+			return true // goAway will close the loop
+		}
+		clientGone := err == io.EOF || err == io.ErrUnexpectedEOF || isClosedConnError(err)
+		if clientGone {
+			// TODO: could we also get into this state if
+			// the peer does a half close
+			// (e.g. CloseWrite) because they're done
+			// sending frames but they're still wanting
+			// our open replies?  Investigate.
+			// TODO: add CloseWrite to crypto/tls.Conn first
+			// so we have a way to test this? I suppose
+			// just for testing we could have a non-TLS mode.
+			return false
+		}
+	} else {
+		f := res.f
+		if VerboseLogs {
+			sc.vlogf("http2: server read frame %v", summarizeFrame(f))
+		}
+		err = sc.processFrame(f)
+		if err == nil {
+			return true
+		}
+	}
+
+	switch ev := err.(type) {
+	case StreamError:
+		sc.resetStream(ev)
+		return true
+	case goAwayFlowError:
+		sc.goAway(ErrCodeFlowControl)
+		return true
+	case ConnectionError:
+		sc.logf("http2: server connection error from %v: %v", sc.conn.RemoteAddr(), ev)
+		sc.goAway(ErrCode(ev))
+		return true // goAway will handle shutdown
+	default:
+		if res.err != nil {
+			sc.vlogf("http2: server closing client connection; error reading frame from client %s: %v", sc.conn.RemoteAddr(), err)
+		} else {
+			sc.logf("http2: server closing client connection: %v", err)
+		}
+		return false
+	}
+}
+
+func (sc *serverConn) processFrame(f Frame) error {
+	sc.serveG.check()
+
+	// First frame received must be SETTINGS.
+	if !sc.sawFirstSettings {
+		if _, ok := f.(*SettingsFrame); !ok {
+			return ConnectionError(ErrCodeProtocol)
+		}
+		sc.sawFirstSettings = true
+	}
+
+	switch f := f.(type) {
+	case *SettingsFrame:
+		return sc.processSettings(f)
+	case *MetaHeadersFrame:
+		return sc.processHeaders(f)
+	case *WindowUpdateFrame:
+		return sc.processWindowUpdate(f)
+	case *PingFrame:
+		return sc.processPing(f)
+	case *DataFrame:
+		return sc.processData(f)
+	case *RSTStreamFrame:
+		return sc.processResetStream(f)
+	case *PriorityFrame:
+		return sc.processPriority(f)
+	case *PushPromiseFrame:
+		// A client cannot push. Thus, servers MUST treat the receipt of a PUSH_PROMISE
+		// frame as a connection error (Section 5.4.1) of type PROTOCOL_ERROR.
+		return ConnectionError(ErrCodeProtocol)
+	default:
+		sc.vlogf("http2: server ignoring frame: %v", f.Header())
+		return nil
+	}
+}
+
+func (sc *serverConn) processPing(f *PingFrame) error {
+	sc.serveG.check()
+	if f.IsAck() {
+		// 6.7 PING: " An endpoint MUST NOT respond to PING frames
+		// containing this flag."
+		return nil
+	}
+	if f.StreamID != 0 {
+		// "PING frames are not associated with any individual
+		// stream. If a PING frame is received with a stream
+		// identifier field value other than 0x0, the recipient MUST
+		// respond with a connection error (Section 5.4.1) of type
+		// PROTOCOL_ERROR."
+		return ConnectionError(ErrCodeProtocol)
+	}
+	sc.writeFrame(frameWriteMsg{write: writePingAck{f}})
+	return nil
+}
+
+func (sc *serverConn) processWindowUpdate(f *WindowUpdateFrame) error {
+	sc.serveG.check()
+	switch {
+	case f.StreamID != 0: // stream-level flow control
+		st := sc.streams[f.StreamID]
+		if st == nil {
+			// "WINDOW_UPDATE can be sent by a peer that has sent a
+			// frame bearing the END_STREAM flag. This means that a
+			// receiver could receive a WINDOW_UPDATE frame on a "half
+			// closed (remote)" or "closed" stream. A receiver MUST
+			// NOT treat this as an error, see Section 5.1."
+			return nil
+		}
+		if !st.flow.add(int32(f.Increment)) {
+			return StreamError{f.StreamID, ErrCodeFlowControl}
+		}
+	default: // connection-level flow control
+		if !sc.flow.add(int32(f.Increment)) {
+			return goAwayFlowError{}
+		}
+	}
+	sc.scheduleFrameWrite()
+	return nil
+}
+
+func (sc *serverConn) processResetStream(f *RSTStreamFrame) error {
+	sc.serveG.check()
+
+	state, st := sc.state(f.StreamID)
+	if state == stateIdle {
+		// 6.4 "RST_STREAM frames MUST NOT be sent for a
+		// stream in the "idle" state. If a RST_STREAM frame
+		// identifying an idle stream is received, the
+		// recipient MUST treat this as a connection error
+		// (Section 5.4.1) of type PROTOCOL_ERROR.
+		return ConnectionError(ErrCodeProtocol)
+	}
+	if st != nil {
+		st.gotReset = true
+		st.cancelCtx()
+		sc.closeStream(st, StreamError{f.StreamID, f.ErrCode})
+	}
+	return nil
+}
+
+func (sc *serverConn) closeStream(st *stream, err error) {
+	sc.serveG.check()
+	if st.state == stateIdle || st.state == stateClosed {
+		panic(fmt.Sprintf("invariant; can't close stream in state %v", st.state))
+	}
+	st.state = stateClosed
+	sc.curOpenStreams--
+	if sc.curOpenStreams == 0 {
+		sc.setConnState(http.StateIdle)
+	}
+	delete(sc.streams, st.id)
+	if p := st.body; p != nil {
+		p.CloseWithError(err)
+	}
+	st.cw.Close() // signals Handler's CloseNotifier, unblocks writes, etc
+	sc.writeSched.forgetStream(st.id)
+	if st.reqBuf != nil {
+		// Stash this request body buffer (64k) away for reuse
+		// by a future POST/PUT/etc.
+		//
+		// TODO(bradfitz): share on the server? sync.Pool?
+		// Server requires locks and might hurt contention.
+		// sync.Pool might work, or might be worse, depending
+		// on goroutine CPU migrations. (get and put on
+		// separate CPUs).  Maybe a mix of strategies. But
+		// this is an easy win for now.
+		sc.freeRequestBodyBuf = st.reqBuf
+	}
+}
+
+func (sc *serverConn) processSettings(f *SettingsFrame) error {
+	sc.serveG.check()
+	if f.IsAck() {
+		sc.unackedSettings--
+		if sc.unackedSettings < 0 {
+			// Why is the peer ACKing settings we never sent?
+			// The spec doesn't mention this case, but
+			// hang up on them anyway.
+			return ConnectionError(ErrCodeProtocol)
+		}
+		return nil
+	}
+	if err := f.ForeachSetting(sc.processSetting); err != nil {
+		return err
+	}
+	sc.needToSendSettingsAck = true
+	sc.scheduleFrameWrite()
+	return nil
+}
+
+func (sc *serverConn) processSetting(s Setting) error {
+	sc.serveG.check()
+	if err := s.Valid(); err != nil {
+		return err
+	}
+	if VerboseLogs {
+		sc.vlogf("http2: server processing setting %v", s)
+	}
+	switch s.ID {
+	case SettingHeaderTableSize:
+		sc.headerTableSize = s.Val
+		sc.hpackEncoder.SetMaxDynamicTableSize(s.Val)
+	case SettingEnablePush:
+		sc.pushEnabled = s.Val != 0
+	case SettingMaxConcurrentStreams:
+		sc.clientMaxStreams = s.Val
+	case SettingInitialWindowSize:
+		return sc.processSettingInitialWindowSize(s.Val)
+	case SettingMaxFrameSize:
+		sc.writeSched.maxFrameSize = s.Val
+	case SettingMaxHeaderListSize:
+		sc.peerMaxHeaderListSize = s.Val
+	default:
+		// Unknown setting: "An endpoint that receives a SETTINGS
+		// frame with any unknown or unsupported identifier MUST
+		// ignore that setting."
+		if VerboseLogs {
+			sc.vlogf("http2: server ignoring unknown setting %v", s)
+		}
+	}
+	return nil
+}
+
+func (sc *serverConn) processSettingInitialWindowSize(val uint32) error {
+	sc.serveG.check()
+	// Note: val already validated to be within range by
+	// processSetting's Valid call.
+
+	// "A SETTINGS frame can alter the initial flow control window
+	// size for all current streams. When the value of
+	// SETTINGS_INITIAL_WINDOW_SIZE changes, a receiver MUST
+	// adjust the size of all stream flow control windows that it
+	// maintains by the difference between the new value and the
+	// old value."
+	old := sc.initialWindowSize
+	sc.initialWindowSize = int32(val)
+	growth := sc.initialWindowSize - old // may be negative
+	for _, st := range sc.streams {
+		if !st.flow.add(growth) {
+			// 6.9.2 Initial Flow Control Window Size
+			// "An endpoint MUST treat a change to
+			// SETTINGS_INITIAL_WINDOW_SIZE that causes any flow
+			// control window to exceed the maximum size as a
+			// connection error (Section 5.4.1) of type
+			// FLOW_CONTROL_ERROR."
+			return ConnectionError(ErrCodeFlowControl)
+		}
+	}
+	return nil
+}
+
+func (sc *serverConn) processData(f *DataFrame) error {
+	sc.serveG.check()
+	// "If a DATA frame is received whose stream is not in "open"
+	// or "half closed (local)" state, the recipient MUST respond
+	// with a stream error (Section 5.4.2) of type STREAM_CLOSED."
+	id := f.Header().StreamID
+	st, ok := sc.streams[id]
+	if !ok || st.state != stateOpen || st.gotTrailerHeader {
+		// This includes sending a RST_STREAM if the stream is
+		// in stateHalfClosedLocal (which currently means that
+		// the http.Handler returned, so it's done reading &
+		// done writing). Try to stop the client from sending
+		// more DATA.
+		return StreamError{id, ErrCodeStreamClosed}
+	}
+	if st.body == nil {
+		panic("internal error: should have a body in this state")
+	}
+	data := f.Data()
+
+	// Sender sending more than they'd declared?
+	if st.declBodyBytes != -1 && st.bodyBytes+int64(len(data)) > st.declBodyBytes {
+		st.body.CloseWithError(fmt.Errorf("sender tried to send more than declared Content-Length of %d bytes", st.declBodyBytes))
+		return StreamError{id, ErrCodeStreamClosed}
+	}
+	if len(data) > 0 {
+		// Check whether the client has flow control quota.
+		if int(st.inflow.available()) < len(data) {
+			return StreamError{id, ErrCodeFlowControl}
+		}
+		st.inflow.take(int32(len(data)))
+		wrote, err := st.body.Write(data)
+		if err != nil {
+			return StreamError{id, ErrCodeStreamClosed}
+		}
+		if wrote != len(data) {
+			panic("internal error: bad Writer")
+		}
+		st.bodyBytes += int64(len(data))
+	}
+	if f.StreamEnded() {
+		st.endStream()
+	}
+	return nil
+}
+
+// endStream closes a Request.Body's pipe. It is called when a DATA
+// frame says a request body is over (or after trailers).
+func (st *stream) endStream() {
+	sc := st.sc
+	sc.serveG.check()
+
+	if st.declBodyBytes != -1 && st.declBodyBytes != st.bodyBytes {
+		st.body.CloseWithError(fmt.Errorf("request declared a Content-Length of %d but only wrote %d bytes",
+			st.declBodyBytes, st.bodyBytes))
+	} else {
+		st.body.closeWithErrorAndCode(io.EOF, st.copyTrailersToHandlerRequest)
+		st.body.CloseWithError(io.EOF)
+	}
+	st.state = stateHalfClosedRemote
+}
+
+// copyTrailersToHandlerRequest is run in the Handler's goroutine in
+// its Request.Body.Read just before it gets io.EOF.
+func (st *stream) copyTrailersToHandlerRequest() {
+	for k, vv := range st.trailer {
+		if _, ok := st.reqTrailer[k]; ok {
+			// Only copy it over it was pre-declared.
+			st.reqTrailer[k] = vv
+		}
+	}
+}
+
+func (sc *serverConn) processHeaders(f *MetaHeadersFrame) error {
+	sc.serveG.check()
+	id := f.Header().StreamID
+	if sc.inGoAway {
+		// Ignore.
+		return nil
+	}
+	// http://http2.github.io/http2-spec/#rfc.section.5.1.1
+	// Streams initiated by a client MUST use odd-numbered stream
+	// identifiers. [...] An endpoint that receives an unexpected
+	// stream identifier MUST respond with a connection error
+	// (Section 5.4.1) of type PROTOCOL_ERROR.
+	if id%2 != 1 {
+		return ConnectionError(ErrCodeProtocol)
+	}
+	// A HEADERS frame can be used to create a new stream or
+	// send a trailer for an open one. If we already have a stream
+	// open, let it process its own HEADERS frame (trailers at this
+	// point, if it's valid).
+	st := sc.streams[f.Header().StreamID]
+	if st != nil {
+		return st.processTrailerHeaders(f)
+	}
+
+	// [...] The identifier of a newly established stream MUST be
+	// numerically greater than all streams that the initiating
+	// endpoint has opened or reserved. [...]  An endpoint that
+	// receives an unexpected stream identifier MUST respond with
+	// a connection error (Section 5.4.1) of type PROTOCOL_ERROR.
+	if id <= sc.maxStreamID {
+		return ConnectionError(ErrCodeProtocol)
+	}
+	sc.maxStreamID = id
+
+	ctx, cancelCtx := contextWithCancel(sc.baseCtx)
+	st = &stream{
+		sc:        sc,
+		id:        id,
+		state:     stateOpen,
+		ctx:       ctx,
+		cancelCtx: cancelCtx,
+	}
+	if f.StreamEnded() {
+		st.state = stateHalfClosedRemote
+	}
+	st.cw.Init()
+
+	st.flow.conn = &sc.flow // link to conn-level counter
+	st.flow.add(sc.initialWindowSize)
+	st.inflow.conn = &sc.inflow      // link to conn-level counter
+	st.inflow.add(initialWindowSize) // TODO: update this when we send a higher initial window size in the initial settings
+
+	sc.streams[id] = st
+	if f.HasPriority() {
+		adjustStreamPriority(sc.streams, st.id, f.Priority)
+	}
+	sc.curOpenStreams++
+	if sc.curOpenStreams == 1 {
+		sc.setConnState(http.StateActive)
+	}
+	if sc.curOpenStreams > sc.advMaxStreams {
+		// "Endpoints MUST NOT exceed the limit set by their
+		// peer. An endpoint that receives a HEADERS frame
+		// that causes their advertised concurrent stream
+		// limit to be exceeded MUST treat this as a stream
+		// error (Section 5.4.2) of type PROTOCOL_ERROR or
+		// REFUSED_STREAM."
+		if sc.unackedSettings == 0 {
+			// They should know better.
+			return StreamError{st.id, ErrCodeProtocol}
+		}
+		// Assume it's a network race, where they just haven't
+		// received our last SETTINGS update. But actually
+		// this can't happen yet, because we don't yet provide
+		// a way for users to adjust server parameters at
+		// runtime.
+		return StreamError{st.id, ErrCodeRefusedStream}
+	}
+
+	rw, req, err := sc.newWriterAndRequest(st, f)
+	if err != nil {
+		return err
+	}
+	st.reqTrailer = req.Trailer
+	if st.reqTrailer != nil {
+		st.trailer = make(http.Header)
+	}
+	st.body = req.Body.(*requestBody).pipe // may be nil
+	st.declBodyBytes = req.ContentLength
+
+	handler := sc.handler.ServeHTTP
+	if f.Truncated {
+		// Their header list was too long. Send a 431 error.
+		handler = handleHeaderListTooLong
+	} else if err := checkValidHTTP2Request(req); err != nil {
+		handler = new400Handler(err)
+	}
+
+	go sc.runHandler(rw, req, handler)
+	return nil
+}
+
+func (st *stream) processTrailerHeaders(f *MetaHeadersFrame) error {
+	sc := st.sc
+	sc.serveG.check()
+	if st.gotTrailerHeader {
+		return ConnectionError(ErrCodeProtocol)
+	}
+	st.gotTrailerHeader = true
+	if !f.StreamEnded() {
+		return StreamError{st.id, ErrCodeProtocol}
+	}
+
+	if len(f.PseudoFields()) > 0 {
+		return StreamError{st.id, ErrCodeProtocol}
+	}
+	if st.trailer != nil {
+		for _, hf := range f.RegularFields() {
+			key := sc.canonicalHeader(hf.Name)
+			if !ValidTrailerHeader(key) {
+				// TODO: send more details to the peer somehow. But http2 has
+				// no way to send debug data at a stream level. Discuss with
+				// HTTP folk.
+				return StreamError{st.id, ErrCodeProtocol}
+			}
+			st.trailer[key] = append(st.trailer[key], hf.Value)
+		}
+	}
+	st.endStream()
+	return nil
+}
+
+func (sc *serverConn) processPriority(f *PriorityFrame) error {
+	adjustStreamPriority(sc.streams, f.StreamID, f.PriorityParam)
+	return nil
+}
+
+func adjustStreamPriority(streams map[uint32]*stream, streamID uint32, priority PriorityParam) {
+	st, ok := streams[streamID]
+	if !ok {
+		// TODO: not quite correct (this streamID might
+		// already exist in the dep tree, but be closed), but
+		// close enough for now.
+		return
+	}
+	st.weight = priority.Weight
+	parent := streams[priority.StreamDep] // might be nil
+	if parent == st {
+		// if client tries to set this stream to be the parent of itself
+		// ignore and keep going
+		return
+	}
+
+	// section 5.3.3: If a stream is made dependent on one of its
+	// own dependencies, the formerly dependent stream is first
+	// moved to be dependent on the reprioritized stream's previous
+	// parent. The moved dependency retains its weight.
+	for piter := parent; piter != nil; piter = piter.parent {
+		if piter == st {
+			parent.parent = st.parent
+			break
+		}
+	}
+	st.parent = parent
+	if priority.Exclusive && (st.parent != nil || priority.StreamDep == 0) {
+		for _, openStream := range streams {
+			if openStream != st && openStream.parent == st.parent {
+				openStream.parent = st
+			}
+		}
+	}
+}
+
+func (sc *serverConn) newWriterAndRequest(st *stream, f *MetaHeadersFrame) (*responseWriter, *http.Request, error) {
+	sc.serveG.check()
+
+	method := f.PseudoValue("method")
+	path := f.PseudoValue("path")
+	scheme := f.PseudoValue("scheme")
+	authority := f.PseudoValue("authority")
+
+	isConnect := method == "CONNECT"
+	if isConnect {
+		if path != "" || scheme != "" || authority == "" {
+			return nil, nil, StreamError{f.StreamID, ErrCodeProtocol}
+		}
+	} else if method == "" || path == "" ||
+		(scheme != "https" && scheme != "http") {
+		// See 8.1.2.6 Malformed Requests and Responses:
+		//
+		// Malformed requests or responses that are detected
+		// MUST be treated as a stream error (Section 5.4.2)
+		// of type PROTOCOL_ERROR."
+		//
+		// 8.1.2.3 Request Pseudo-Header Fields
+		// "All HTTP/2 requests MUST include exactly one valid
+		// value for the :method, :scheme, and :path
+		// pseudo-header fields"
+		return nil, nil, StreamError{f.StreamID, ErrCodeProtocol}
+	}
+
+	bodyOpen := !f.StreamEnded()
+	if method == "HEAD" && bodyOpen {
+		// HEAD requests can't have bodies
+		return nil, nil, StreamError{f.StreamID, ErrCodeProtocol}
+	}
+	var tlsState *tls.ConnectionState // nil if not scheme https
+
+	if scheme == "https" {
+		tlsState = sc.tlsState
+	}
+
+	header := make(http.Header)
+	for _, hf := range f.RegularFields() {
+		header.Add(sc.canonicalHeader(hf.Name), hf.Value)
+	}
+
+	if authority == "" {
+		authority = header.Get("Host")
+	}
+	needsContinue := header.Get("Expect") == "100-continue"
+	if needsContinue {
+		header.Del("Expect")
+	}
+	// Merge Cookie headers into one "; "-delimited value.
+	if cookies := header["Cookie"]; len(cookies) > 1 {
+		header.Set("Cookie", strings.Join(cookies, "; "))
+	}
+
+	// Setup Trailers
+	var trailer http.Header
+	for _, v := range header["Trailer"] {
+		for _, key := range strings.Split(v, ",") {
+			key = http.CanonicalHeaderKey(strings.TrimSpace(key))
+			switch key {
+			case "Transfer-Encoding", "Trailer", "Content-Length":
+				// Bogus. (copy of http1 rules)
+				// Ignore.
+			default:
+				if trailer == nil {
+					trailer = make(http.Header)
+				}
+				trailer[key] = nil
+			}
+		}
+	}
+	delete(header, "Trailer")
+
+	body := &requestBody{
+		conn:          sc,
+		stream:        st,
+		needsContinue: needsContinue,
+	}
+	var url_ *url.URL
+	var requestURI string
+	if isConnect {
+		url_ = &url.URL{Host: authority}
+		requestURI = authority // mimic HTTP/1 server behavior
+	} else {
+		var err error
+		url_, err = url.ParseRequestURI(path)
+		if err != nil {
+			return nil, nil, StreamError{f.StreamID, ErrCodeProtocol}
+		}
+		requestURI = path
+	}
+	req := &http.Request{
+		Method:     method,
+		URL:        url_,
+		RemoteAddr: sc.remoteAddrStr,
+		Header:     header,
+		RequestURI: requestURI,
+		Proto:      "HTTP/2.0",
+		ProtoMajor: 2,
+		ProtoMinor: 0,
+		TLS:        tlsState,
+		Host:       authority,
+		Body:       body,
+		Trailer:    trailer,
+	}
+	req = requestWithContext(req, st.ctx)
+	if bodyOpen {
+		// Disabled, per golang.org/issue/14960:
+		// st.reqBuf = sc.getRequestBodyBuf()
+		// TODO: remove this 64k of garbage per request (again, but without a data race):
+		buf := make([]byte, initialWindowSize)
+
+		body.pipe = &pipe{
+			b: &fixedBuffer{buf: buf},
+		}
+
+		if vv, ok := header["Content-Length"]; ok {
+			req.ContentLength, _ = strconv.ParseInt(vv[0], 10, 64)
+		} else {
+			req.ContentLength = -1
+		}
+	}
+
+	rws := responseWriterStatePool.Get().(*responseWriterState)
+	bwSave := rws.bw
+	*rws = responseWriterState{} // zero all the fields
+	rws.conn = sc
+	rws.bw = bwSave
+	rws.bw.Reset(chunkWriter{rws})
+	rws.stream = st
+	rws.req = req
+	rws.body = body
+
+	rw := &responseWriter{rws: rws}
+	return rw, req, nil
+}
+
+func (sc *serverConn) getRequestBodyBuf() []byte {
+	sc.serveG.check()
+	if buf := sc.freeRequestBodyBuf; buf != nil {
+		sc.freeRequestBodyBuf = nil
+		return buf
+	}
+	return make([]byte, initialWindowSize)
+}
+
+// Run on its own goroutine.
+func (sc *serverConn) runHandler(rw *responseWriter, req *http.Request, handler func(http.ResponseWriter, *http.Request)) {
+	didPanic := true
+	defer func() {
+		rw.rws.stream.cancelCtx()
+		if didPanic {
+			e := recover()
+			// Same as net/http:
+			const size = 64 << 10
+			buf := make([]byte, size)
+			buf = buf[:runtime.Stack(buf, false)]
+			sc.writeFrameFromHandler(frameWriteMsg{
+				write:  handlerPanicRST{rw.rws.stream.id},
+				stream: rw.rws.stream,
+			})
+			sc.logf("http2: panic serving %v: %v\n%s", sc.conn.RemoteAddr(), e, buf)
+			return
+		}
+		rw.handlerDone()
+	}()
+	handler(rw, req)
+	didPanic = false
+}
+
+func handleHeaderListTooLong(w http.ResponseWriter, r *http.Request) {
+	// 10.5.1 Limits on Header Block Size:
+	// .. "A server that receives a larger header block than it is
+	// willing to handle can send an HTTP 431 (Request Header Fields Too
+	// Large) status code"
+	const statusRequestHeaderFieldsTooLarge = 431 // only in Go 1.6+
+	w.WriteHeader(statusRequestHeaderFieldsTooLarge)
+	io.WriteString(w, "<h1>HTTP Error 431</h1><p>Request Header Field(s) Too Large</p>")
+}
+
+// called from handler goroutines.
+// h may be nil.
+func (sc *serverConn) writeHeaders(st *stream, headerData *writeResHeaders) error {
+	sc.serveG.checkNotOn() // NOT on
+	var errc chan error
+	if headerData.h != nil {
+		// If there's a header map (which we don't own), so we have to block on
+		// waiting for this frame to be written, so an http.Flush mid-handler
+		// writes out the correct value of keys, before a handler later potentially
+		// mutates it.
+		errc = errChanPool.Get().(chan error)
+	}
+	if err := sc.writeFrameFromHandler(frameWriteMsg{
+		write:  headerData,
+		stream: st,
+		done:   errc,
+	}); err != nil {
+		return err
+	}
+	if errc != nil {
+		select {
+		case err := <-errc:
+			errChanPool.Put(errc)
+			return err
+		case <-sc.doneServing:
+			return errClientDisconnected
+		case <-st.cw:
+			return errStreamClosed
+		}
+	}
+	return nil
+}
+
+// called from handler goroutines.
+func (sc *serverConn) write100ContinueHeaders(st *stream) {
+	sc.writeFrameFromHandler(frameWriteMsg{
+		write:  write100ContinueHeadersFrame{st.id},
+		stream: st,
+	})
+}
+
+// A bodyReadMsg tells the server loop that the http.Handler read n
+// bytes of the DATA from the client on the given stream.
+type bodyReadMsg struct {
+	st *stream
+	n  int
+}
+
+// called from handler goroutines.
+// Notes that the handler for the given stream ID read n bytes of its body
+// and schedules flow control tokens to be sent.
+func (sc *serverConn) noteBodyReadFromHandler(st *stream, n int) {
+	sc.serveG.checkNotOn() // NOT on
+	select {
+	case sc.bodyReadCh <- bodyReadMsg{st, n}:
+	case <-sc.doneServing:
+	}
+}
+
+func (sc *serverConn) noteBodyRead(st *stream, n int) {
+	sc.serveG.check()
+	sc.sendWindowUpdate(nil, n) // conn-level
+	if st.state != stateHalfClosedRemote && st.state != stateClosed {
+		// Don't send this WINDOW_UPDATE if the stream is closed
+		// remotely.
+		sc.sendWindowUpdate(st, n)
+	}
+}
+
+// st may be nil for conn-level
+func (sc *serverConn) sendWindowUpdate(st *stream, n int) {
+	sc.serveG.check()
+	// "The legal range for the increment to the flow control
+	// window is 1 to 2^31-1 (2,147,483,647) octets."
+	// A Go Read call on 64-bit machines could in theory read
+	// a larger Read than this. Very unlikely, but we handle it here
+	// rather than elsewhere for now.
+	const maxUint31 = 1<<31 - 1
+	for n >= maxUint31 {
+		sc.sendWindowUpdate32(st, maxUint31)
+		n -= maxUint31
+	}
+	sc.sendWindowUpdate32(st, int32(n))
+}
+
+// st may be nil for conn-level
+func (sc *serverConn) sendWindowUpdate32(st *stream, n int32) {
+	sc.serveG.check()
+	if n == 0 {
+		return
+	}
+	if n < 0 {
+		panic("negative update")
+	}
+	var streamID uint32
+	if st != nil {
+		streamID = st.id
+	}
+	sc.writeFrame(frameWriteMsg{
+		write:  writeWindowUpdate{streamID: streamID, n: uint32(n)},
+		stream: st,
+	})
+	var ok bool
+	if st == nil {
+		ok = sc.inflow.add(n)
+	} else {
+		ok = st.inflow.add(n)
+	}
+	if !ok {
+		panic("internal error; sent too many window updates without decrements?")
+	}
+}
+
+type requestBody struct {
+	stream        *stream
+	conn          *serverConn
+	closed        bool
+	pipe          *pipe // non-nil if we have a HTTP entity message body
+	needsContinue bool  // need to send a 100-continue
+}
+
+func (b *requestBody) Close() error {
+	if b.pipe != nil {
+		b.pipe.BreakWithError(errClosedBody)
+	}
+	b.closed = true
+	return nil
+}
+
+func (b *requestBody) Read(p []byte) (n int, err error) {
+	if b.needsContinue {
+		b.needsContinue = false
+		b.conn.write100ContinueHeaders(b.stream)
+	}
+	if b.pipe == nil {
+		return 0, io.EOF
+	}
+	n, err = b.pipe.Read(p)
+	if n > 0 {
+		b.conn.noteBodyReadFromHandler(b.stream, n)
+	}
+	return
+}
+
+// responseWriter is the http.ResponseWriter implementation.  It's
+// intentionally small (1 pointer wide) to minimize garbage.  The
+// responseWriterState pointer inside is zeroed at the end of a
+// request (in handlerDone) and calls on the responseWriter thereafter
+// simply crash (caller's mistake), but the much larger responseWriterState
+// and buffers are reused between multiple requests.
+type responseWriter struct {
+	rws *responseWriterState
+}
+
+// Optional http.ResponseWriter interfaces implemented.
+var (
+	_ http.CloseNotifier = (*responseWriter)(nil)
+	_ http.Flusher       = (*responseWriter)(nil)
+	_ stringWriter       = (*responseWriter)(nil)
+)
+
+type responseWriterState struct {
+	// immutable within a request:
+	stream *stream
+	req    *http.Request
+	body   *requestBody // to close at end of request, if DATA frames didn't
+	conn   *serverConn
+
+	// TODO: adjust buffer writing sizes based on server config, frame size updates from peer, etc
+	bw *bufio.Writer // writing to a chunkWriter{this *responseWriterState}
+
+	// mutated by http.Handler goroutine:
+	handlerHeader http.Header // nil until called
+	snapHeader    http.Header // snapshot of handlerHeader at WriteHeader time
+	trailers      []string    // set in writeChunk
+	status        int         // status code passed to WriteHeader
+	wroteHeader   bool        // WriteHeader called (explicitly or implicitly). Not necessarily sent to user yet.
+	sentHeader    bool        // have we sent the header frame?
+	handlerDone   bool        // handler has finished
+
+	sentContentLen int64 // non-zero if handler set a Content-Length header
+	wroteBytes     int64
+
+	closeNotifierMu sync.Mutex // guards closeNotifierCh
+	closeNotifierCh chan bool  // nil until first used
+}
+
+type chunkWriter struct{ rws *responseWriterState }
+
+func (cw chunkWriter) Write(p []byte) (n int, err error) { return cw.rws.writeChunk(p) }
+
+func (rws *responseWriterState) hasTrailers() bool { return len(rws.trailers) != 0 }
+
+// declareTrailer is called for each Trailer header when the
+// response header is written. It notes that a header will need to be
+// written in the trailers at the end of the response.
+func (rws *responseWriterState) declareTrailer(k string) {
+	k = http.CanonicalHeaderKey(k)
+	if !ValidTrailerHeader(k) {
+		// Forbidden by RFC 2616 14.40.
+		rws.conn.logf("ignoring invalid trailer %q", k)
+		return
+	}
+	if !strSliceContains(rws.trailers, k) {
+		rws.trailers = append(rws.trailers, k)
+	}
+}
+
+// writeChunk writes chunks from the bufio.Writer. But because
+// bufio.Writer may bypass its chunking, sometimes p may be
+// arbitrarily large.
+//
+// writeChunk is also responsible (on the first chunk) for sending the
+// HEADER response.
+func (rws *responseWriterState) writeChunk(p []byte) (n int, err error) {
+	if !rws.wroteHeader {
+		rws.writeHeader(200)
+	}
+
+	isHeadResp := rws.req.Method == "HEAD"
+	if !rws.sentHeader {
+		rws.sentHeader = true
+		var ctype, clen string
+		if clen = rws.snapHeader.Get("Content-Length"); clen != "" {
+			rws.snapHeader.Del("Content-Length")
+			clen64, err := strconv.ParseInt(clen, 10, 64)
+			if err == nil && clen64 >= 0 {
+				rws.sentContentLen = clen64
+			} else {
+				clen = ""
+			}
+		}
+		if clen == "" && rws.handlerDone && bodyAllowedForStatus(rws.status) && (len(p) > 0 || !isHeadResp) {
+			clen = strconv.Itoa(len(p))
+		}
+		_, hasContentType := rws.snapHeader["Content-Type"]
+		if !hasContentType && bodyAllowedForStatus(rws.status) {
+			ctype = http.DetectContentType(p)
+		}
+		var date string
+		if _, ok := rws.snapHeader["Date"]; !ok {
+			// TODO(bradfitz): be faster here, like net/http? measure.
+			date = time.Now().UTC().Format(http.TimeFormat)
+		}
+
+		for _, v := range rws.snapHeader["Trailer"] {
+			foreachHeaderElement(v, rws.declareTrailer)
+		}
+
+		endStream := (rws.handlerDone && !rws.hasTrailers() && len(p) == 0) || isHeadResp
+		err = rws.conn.writeHeaders(rws.stream, &writeResHeaders{
+			streamID:      rws.stream.id,
+			httpResCode:   rws.status,
+			h:             rws.snapHeader,
+			endStream:     endStream,
+			contentType:   ctype,
+			contentLength: clen,
+			date:          date,
+		})
+		if err != nil {
+			return 0, err
+		}
+		if endStream {
+			return 0, nil
+		}
+	}
+	if isHeadResp {
+		return len(p), nil
+	}
+	if len(p) == 0 && !rws.handlerDone {
+		return 0, nil
+	}
+
+	if rws.handlerDone {
+		rws.promoteUndeclaredTrailers()
+	}
+
+	endStream := rws.handlerDone && !rws.hasTrailers()
+	if len(p) > 0 || endStream {
+		// only send a 0 byte DATA frame if we're ending the stream.
+		if err := rws.conn.writeDataFromHandler(rws.stream, p, endStream); err != nil {
+			return 0, err
+		}
+	}
+
+	if rws.handlerDone && rws.hasTrailers() {
+		err = rws.conn.writeHeaders(rws.stream, &writeResHeaders{
+			streamID:  rws.stream.id,
+			h:         rws.handlerHeader,
+			trailers:  rws.trailers,
+			endStream: true,
+		})
+		return len(p), err
+	}
+	return len(p), nil
+}
+
+// TrailerPrefix is a magic prefix for ResponseWriter.Header map keys
+// that, if present, signals that the map entry is actually for
+// the response trailers, and not the response headers. The prefix
+// is stripped after the ServeHTTP call finishes and the values are
+// sent in the trailers.
+//
+// This mechanism is intended only for trailers that are not known
+// prior to the headers being written. If the set of trailers is fixed
+// or known before the header is written, the normal Go trailers mechanism
+// is preferred:
+//    https://golang.org/pkg/net/http/#ResponseWriter
+//    https://golang.org/pkg/net/http/#example_ResponseWriter_trailers
+const TrailerPrefix = "Trailer:"
+
+// promoteUndeclaredTrailers permits http.Handlers to set trailers
+// after the header has already been flushed. Because the Go
+// ResponseWriter interface has no way to set Trailers (only the
+// Header), and because we didn't want to expand the ResponseWriter
+// interface, and because nobody used trailers, and because RFC 2616
+// says you SHOULD (but not must) predeclare any trailers in the
+// header, the official ResponseWriter rules said trailers in Go must
+// be predeclared, and then we reuse the same ResponseWriter.Header()
+// map to mean both Headers and Trailers.  When it's time to write the
+// Trailers, we pick out the fields of Headers that were declared as
+// trailers. That worked for a while, until we found the first major
+// user of Trailers in the wild: gRPC (using them only over http2),
+// and gRPC libraries permit setting trailers mid-stream without
+// predeclarnig them. So: change of plans. We still permit the old
+// way, but we also permit this hack: if a Header() key begins with
+// "Trailer:", the suffix of that key is a Trailer. Because ':' is an
+// invalid token byte anyway, there is no ambiguity. (And it's already
+// filtered out) It's mildly hacky, but not terrible.
+//
+// This method runs after the Handler is done and promotes any Header
+// fields to be trailers.
+func (rws *responseWriterState) promoteUndeclaredTrailers() {
+	for k, vv := range rws.handlerHeader {
+		if !strings.HasPrefix(k, TrailerPrefix) {
+			continue
+		}
+		trailerKey := strings.TrimPrefix(k, TrailerPrefix)
+		rws.declareTrailer(trailerKey)
+		rws.handlerHeader[http.CanonicalHeaderKey(trailerKey)] = vv
+	}
+
+	if len(rws.trailers) > 1 {
+		sorter := sorterPool.Get().(*sorter)
+		sorter.SortStrings(rws.trailers)
+		sorterPool.Put(sorter)
+	}
+}
+
+func (w *responseWriter) Flush() {
+	rws := w.rws
+	if rws == nil {
+		panic("Header called after Handler finished")
+	}
+	if rws.bw.Buffered() > 0 {
+		if err := rws.bw.Flush(); err != nil {
+			// Ignore the error. The frame writer already knows.
+			return
+		}
+	} else {
+		// The bufio.Writer won't call chunkWriter.Write
+		// (writeChunk with zero bytes, so we have to do it
+		// ourselves to force the HTTP response header and/or
+		// final DATA frame (with END_STREAM) to be sent.
+		rws.writeChunk(nil)
+	}
+}
+
+func (w *responseWriter) CloseNotify() <-chan bool {
+	rws := w.rws
+	if rws == nil {
+		panic("CloseNotify called after Handler finished")
+	}
+	rws.closeNotifierMu.Lock()
+	ch := rws.closeNotifierCh
+	if ch == nil {
+		ch = make(chan bool, 1)
+		rws.closeNotifierCh = ch
+		go func() {
+			rws.stream.cw.Wait() // wait for close
+			ch <- true
+		}()
+	}
+	rws.closeNotifierMu.Unlock()
+	return ch
+}
+
+func (w *responseWriter) Header() http.Header {
+	rws := w.rws
+	if rws == nil {
+		panic("Header called after Handler finished")
+	}
+	if rws.handlerHeader == nil {
+		rws.handlerHeader = make(http.Header)
+	}
+	return rws.handlerHeader
+}
+
+func (w *responseWriter) WriteHeader(code int) {
+	rws := w.rws
+	if rws == nil {
+		panic("WriteHeader called after Handler finished")
+	}
+	rws.writeHeader(code)
+}
+
+func (rws *responseWriterState) writeHeader(code int) {
+	if !rws.wroteHeader {
+		rws.wroteHeader = true
+		rws.status = code
+		if len(rws.handlerHeader) > 0 {
+			rws.snapHeader = cloneHeader(rws.handlerHeader)
+		}
+	}
+}
+
+func cloneHeader(h http.Header) http.Header {
+	h2 := make(http.Header, len(h))
+	for k, vv := range h {
+		vv2 := make([]string, len(vv))
+		copy(vv2, vv)
+		h2[k] = vv2
+	}
+	return h2
+}
+
+// The Life Of A Write is like this:
+//
+// * Handler calls w.Write or w.WriteString ->
+// * -> rws.bw (*bufio.Writer) ->
+// * (Handler migth call Flush)
+// * -> chunkWriter{rws}
+// * -> responseWriterState.writeChunk(p []byte)
+// * -> responseWriterState.writeChunk (most of the magic; see comment there)
+func (w *responseWriter) Write(p []byte) (n int, err error) {
+	return w.write(len(p), p, "")
+}
+
+func (w *responseWriter) WriteString(s string) (n int, err error) {
+	return w.write(len(s), nil, s)
+}
+
+// either dataB or dataS is non-zero.
+func (w *responseWriter) write(lenData int, dataB []byte, dataS string) (n int, err error) {
+	rws := w.rws
+	if rws == nil {
+		panic("Write called after Handler finished")
+	}
+	if !rws.wroteHeader {
+		w.WriteHeader(200)
+	}
+	if !bodyAllowedForStatus(rws.status) {
+		return 0, http.ErrBodyNotAllowed
+	}
+	rws.wroteBytes += int64(len(dataB)) + int64(len(dataS)) // only one can be set
+	if rws.sentContentLen != 0 && rws.wroteBytes > rws.sentContentLen {
+		// TODO: send a RST_STREAM
+		return 0, errors.New("http2: handler wrote more than declared Content-Length")
+	}
+
+	if dataB != nil {
+		return rws.bw.Write(dataB)
+	} else {
+		return rws.bw.WriteString(dataS)
+	}
+}
+
+func (w *responseWriter) handlerDone() {
+	rws := w.rws
+	rws.handlerDone = true
+	w.Flush()
+	w.rws = nil
+	responseWriterStatePool.Put(rws)
+}
+
+// foreachHeaderElement splits v according to the "#rule" construction
+// in RFC 2616 section 2.1 and calls fn for each non-empty element.
+func foreachHeaderElement(v string, fn func(string)) {
+	v = textproto.TrimString(v)
+	if v == "" {
+		return
+	}
+	if !strings.Contains(v, ",") {
+		fn(v)
+		return
+	}
+	for _, f := range strings.Split(v, ",") {
+		if f = textproto.TrimString(f); f != "" {
+			fn(f)
+		}
+	}
+}
+
+// From http://httpwg.org/specs/rfc7540.html#rfc.section.8.1.2.2
+var connHeaders = []string{
+	"Connection",
+	"Keep-Alive",
+	"Proxy-Connection",
+	"Transfer-Encoding",
+	"Upgrade",
+}
+
+// checkValidHTTP2Request checks whether req is a valid HTTP/2 request,
+// per RFC 7540 Section 8.1.2.2.
+// The returned error is reported to users.
+func checkValidHTTP2Request(req *http.Request) error {
+	for _, h := range connHeaders {
+		if _, ok := req.Header[h]; ok {
+			return fmt.Errorf("request header %q is not valid in HTTP/2", h)
+		}
+	}
+	te := req.Header["Te"]
+	if len(te) > 0 && (len(te) > 1 || (te[0] != "trailers" && te[0] != "")) {
+		return errors.New(`request header "TE" may only be "trailers" in HTTP/2`)
+	}
+	return nil
+}
+
+func new400Handler(err error) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+	}
+}
+
+// ValidTrailerHeader reports whether name is a valid header field name to appear
+// in trailers.
+// See: http://tools.ietf.org/html/rfc7230#section-4.1.2
+func ValidTrailerHeader(name string) bool {
+	name = http.CanonicalHeaderKey(name)
+	if strings.HasPrefix(name, "If-") || badTrailer[name] {
+		return false
+	}
+	return true
+}
+
+var badTrailer = map[string]bool{
+	"Authorization":       true,
+	"Cache-Control":       true,
+	"Connection":          true,
+	"Content-Encoding":    true,
+	"Content-Length":      true,
+	"Content-Range":       true,
+	"Content-Type":        true,
+	"Expect":              true,
+	"Host":                true,
+	"Keep-Alive":          true,
+	"Max-Forwards":        true,
+	"Pragma":              true,
+	"Proxy-Authenticate":  true,
+	"Proxy-Authorization": true,
+	"Proxy-Connection":    true,
+	"Range":               true,
+	"Realm":               true,
+	"Te":                  true,
+	"Trailer":             true,
+	"Transfer-Encoding":   true,
+	"Www-Authenticate":    true,
+}
diff --git a/vendor/golang.org/x/net/http2/transport.go b/vendor/golang.org/x/net/http2/transport.go
new file mode 100644
index 0000000..2ae7437
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/transport.go
@@ -0,0 +1,1816 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Transport code.
+
+package http2
+
+import (
+	"bufio"
+	"bytes"
+	"compress/gzip"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"sort"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/net/http2/hpack"
+	"golang.org/x/net/lex/httplex"
+)
+
+const (
+	// transportDefaultConnFlow is how many connection-level flow control
+	// tokens we give the server at start-up, past the default 64k.
+	transportDefaultConnFlow = 1 << 30
+
+	// transportDefaultStreamFlow is how many stream-level flow
+	// control tokens we announce to the peer, and how many bytes
+	// we buffer per stream.
+	transportDefaultStreamFlow = 4 << 20
+
+	// transportDefaultStreamMinRefresh is the minimum number of bytes we'll send
+	// a stream-level WINDOW_UPDATE for at a time.
+	transportDefaultStreamMinRefresh = 4 << 10
+
+	defaultUserAgent = "Go-http-client/2.0"
+)
+
+// Transport is an HTTP/2 Transport.
+//
+// A Transport internally caches connections to servers. It is safe
+// for concurrent use by multiple goroutines.
+type Transport struct {
+	// DialTLS specifies an optional dial function for creating
+	// TLS connections for requests.
+	//
+	// If DialTLS is nil, tls.Dial is used.
+	//
+	// If the returned net.Conn has a ConnectionState method like tls.Conn,
+	// it will be used to set http.Response.TLS.
+	DialTLS func(network, addr string, cfg *tls.Config) (net.Conn, error)
+
+	// TLSClientConfig specifies the TLS configuration to use with
+	// tls.Client. If nil, the default configuration is used.
+	TLSClientConfig *tls.Config
+
+	// ConnPool optionally specifies an alternate connection pool to use.
+	// If nil, the default is used.
+	ConnPool ClientConnPool
+
+	// DisableCompression, if true, prevents the Transport from
+	// requesting compression with an "Accept-Encoding: gzip"
+	// request header when the Request contains no existing
+	// Accept-Encoding value. If the Transport requests gzip on
+	// its own and gets a gzipped response, it's transparently
+	// decoded in the Response.Body. However, if the user
+	// explicitly requested gzip it is not automatically
+	// uncompressed.
+	DisableCompression bool
+
+	// MaxHeaderListSize is the http2 SETTINGS_MAX_HEADER_LIST_SIZE to
+	// send in the initial settings frame. It is how many bytes
+	// of response headers are allow. Unlike the http2 spec, zero here
+	// means to use a default limit (currently 10MB). If you actually
+	// want to advertise an ulimited value to the peer, Transport
+	// interprets the highest possible value here (0xffffffff or 1<<32-1)
+	// to mean no limit.
+	MaxHeaderListSize uint32
+
+	// t1, if non-nil, is the standard library Transport using
+	// this transport. Its settings are used (but not its
+	// RoundTrip method, etc).
+	t1 *http.Transport
+
+	connPoolOnce  sync.Once
+	connPoolOrDef ClientConnPool // non-nil version of ConnPool
+}
+
+func (t *Transport) maxHeaderListSize() uint32 {
+	if t.MaxHeaderListSize == 0 {
+		return 10 << 20
+	}
+	if t.MaxHeaderListSize == 0xffffffff {
+		return 0
+	}
+	return t.MaxHeaderListSize
+}
+
+func (t *Transport) disableCompression() bool {
+	return t.DisableCompression || (t.t1 != nil && t.t1.DisableCompression)
+}
+
+var errTransportVersion = errors.New("http2: ConfigureTransport is only supported starting at Go 1.6")
+
+// ConfigureTransport configures a net/http HTTP/1 Transport to use HTTP/2.
+// It requires Go 1.6 or later and returns an error if the net/http package is too old
+// or if t1 has already been HTTP/2-enabled.
+func ConfigureTransport(t1 *http.Transport) error {
+	_, err := configureTransport(t1) // in configure_transport.go (go1.6) or not_go16.go
+	return err
+}
+
+func (t *Transport) connPool() ClientConnPool {
+	t.connPoolOnce.Do(t.initConnPool)
+	return t.connPoolOrDef
+}
+
+func (t *Transport) initConnPool() {
+	if t.ConnPool != nil {
+		t.connPoolOrDef = t.ConnPool
+	} else {
+		t.connPoolOrDef = &clientConnPool{t: t}
+	}
+}
+
+// ClientConn is the state of a single HTTP/2 client connection to an
+// HTTP/2 server.
+type ClientConn struct {
+	t        *Transport
+	tconn    net.Conn             // usually *tls.Conn, except specialized impls
+	tlsState *tls.ConnectionState // nil only for specialized impls
+
+	// readLoop goroutine fields:
+	readerDone chan struct{} // closed on error
+	readerErr  error         // set before readerDone is closed
+
+	mu           sync.Mutex // guards following
+	cond         *sync.Cond // hold mu; broadcast on flow/closed changes
+	flow         flow       // our conn-level flow control quota (cs.flow is per stream)
+	inflow       flow       // peer's conn-level flow control
+	closed       bool
+	goAway       *GoAwayFrame             // if non-nil, the GoAwayFrame we received
+	streams      map[uint32]*clientStream // client-initiated
+	nextStreamID uint32
+	bw           *bufio.Writer
+	br           *bufio.Reader
+	fr           *Framer
+	lastActive   time.Time
+
+	// Settings from peer:
+	maxFrameSize         uint32
+	maxConcurrentStreams uint32
+	initialWindowSize    uint32
+	hbuf                 bytes.Buffer // HPACK encoder writes into this
+	henc                 *hpack.Encoder
+	freeBuf              [][]byte
+
+	wmu  sync.Mutex // held while writing; acquire AFTER mu if holding both
+	werr error      // first write error that has occurred
+}
+
+// clientStream is the state for a single HTTP/2 stream. One of these
+// is created for each Transport.RoundTrip call.
+type clientStream struct {
+	cc            *ClientConn
+	req           *http.Request
+	trace         *clientTrace // or nil
+	ID            uint32
+	resc          chan resAndError
+	bufPipe       pipe // buffered pipe with the flow-controlled response payload
+	requestedGzip bool
+	on100         func() // optional code to run if get a 100 continue response
+
+	flow        flow  // guarded by cc.mu
+	inflow      flow  // guarded by cc.mu
+	bytesRemain int64 // -1 means unknown; owned by transportResponseBody.Read
+	readErr     error // sticky read error; owned by transportResponseBody.Read
+	stopReqBody error // if non-nil, stop writing req body; guarded by cc.mu
+
+	peerReset chan struct{} // closed on peer reset
+	resetErr  error         // populated before peerReset is closed
+
+	done chan struct{} // closed when stream remove from cc.streams map; close calls guarded by cc.mu
+
+	// owned by clientConnReadLoop:
+	pastHeaders  bool // got first MetaHeadersFrame (actual headers)
+	pastTrailers bool // got optional second MetaHeadersFrame (trailers)
+
+	trailer    http.Header  // accumulated trailers
+	resTrailer *http.Header // client's Response.Trailer
+}
+
+// awaitRequestCancel runs in its own goroutine and waits for the user
+// to cancel a RoundTrip request, its context to expire, or for the
+// request to be done (any way it might be removed from the cc.streams
+// map: peer reset, successful completion, TCP connection breakage,
+// etc)
+func (cs *clientStream) awaitRequestCancel(req *http.Request) {
+	ctx := reqContext(req)
+	if req.Cancel == nil && ctx.Done() == nil {
+		return
+	}
+	select {
+	case <-req.Cancel:
+		cs.bufPipe.CloseWithError(errRequestCanceled)
+		cs.cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
+	case <-ctx.Done():
+		cs.bufPipe.CloseWithError(ctx.Err())
+		cs.cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
+	case <-cs.done:
+	}
+}
+
+// checkResetOrDone reports any error sent in a RST_STREAM frame by the
+// server, or errStreamClosed if the stream is complete.
+func (cs *clientStream) checkResetOrDone() error {
+	select {
+	case <-cs.peerReset:
+		return cs.resetErr
+	case <-cs.done:
+		return errStreamClosed
+	default:
+		return nil
+	}
+}
+
+func (cs *clientStream) abortRequestBodyWrite(err error) {
+	if err == nil {
+		panic("nil error")
+	}
+	cc := cs.cc
+	cc.mu.Lock()
+	cs.stopReqBody = err
+	cc.cond.Broadcast()
+	cc.mu.Unlock()
+}
+
+type stickyErrWriter struct {
+	w   io.Writer
+	err *error
+}
+
+func (sew stickyErrWriter) Write(p []byte) (n int, err error) {
+	if *sew.err != nil {
+		return 0, *sew.err
+	}
+	n, err = sew.w.Write(p)
+	*sew.err = err
+	return
+}
+
+var ErrNoCachedConn = errors.New("http2: no cached connection was available")
+
+// RoundTripOpt are options for the Transport.RoundTripOpt method.
+type RoundTripOpt struct {
+	// OnlyCachedConn controls whether RoundTripOpt may
+	// create a new TCP connection. If set true and
+	// no cached connection is available, RoundTripOpt
+	// will return ErrNoCachedConn.
+	OnlyCachedConn bool
+}
+
+func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
+	return t.RoundTripOpt(req, RoundTripOpt{})
+}
+
+// authorityAddr returns a given authority (a host/IP, or host:port / ip:port)
+// and returns a host:port. The port 443 is added if needed.
+func authorityAddr(authority string) (addr string) {
+	if _, _, err := net.SplitHostPort(authority); err == nil {
+		return authority
+	}
+	return net.JoinHostPort(authority, "443")
+}
+
+// RoundTripOpt is like RoundTrip, but takes options.
+func (t *Transport) RoundTripOpt(req *http.Request, opt RoundTripOpt) (*http.Response, error) {
+	if req.URL.Scheme != "https" {
+		return nil, errors.New("http2: unsupported scheme")
+	}
+
+	addr := authorityAddr(req.URL.Host)
+	for {
+		cc, err := t.connPool().GetClientConn(req, addr)
+		if err != nil {
+			t.vlogf("http2: Transport failed to get client conn for %s: %v", addr, err)
+			return nil, err
+		}
+		traceGotConn(req, cc)
+		res, err := cc.RoundTrip(req)
+		if shouldRetryRequest(req, err) {
+			continue
+		}
+		if err != nil {
+			t.vlogf("RoundTrip failure: %v", err)
+			return nil, err
+		}
+		return res, nil
+	}
+}
+
+// CloseIdleConnections closes any connections which were previously
+// connected from previous requests but are now sitting idle.
+// It does not interrupt any connections currently in use.
+func (t *Transport) CloseIdleConnections() {
+	if cp, ok := t.connPool().(clientConnPoolIdleCloser); ok {
+		cp.closeIdleConnections()
+	}
+}
+
+var (
+	errClientConnClosed   = errors.New("http2: client conn is closed")
+	errClientConnUnusable = errors.New("http2: client conn not usable")
+)
+
+func shouldRetryRequest(req *http.Request, err error) bool {
+	// TODO: retry GET requests (no bodies) more aggressively, if shutdown
+	// before response.
+	return err == errClientConnUnusable
+}
+
+func (t *Transport) dialClientConn(addr string) (*ClientConn, error) {
+	host, _, err := net.SplitHostPort(addr)
+	if err != nil {
+		return nil, err
+	}
+	tconn, err := t.dialTLS()("tcp", addr, t.newTLSConfig(host))
+	if err != nil {
+		return nil, err
+	}
+	return t.NewClientConn(tconn)
+}
+
+func (t *Transport) newTLSConfig(host string) *tls.Config {
+	cfg := new(tls.Config)
+	if t.TLSClientConfig != nil {
+		*cfg = *t.TLSClientConfig
+	}
+	if !strSliceContains(cfg.NextProtos, NextProtoTLS) {
+		cfg.NextProtos = append([]string{NextProtoTLS}, cfg.NextProtos...)
+	}
+	if cfg.ServerName == "" {
+		cfg.ServerName = host
+	}
+	return cfg
+}
+
+func (t *Transport) dialTLS() func(string, string, *tls.Config) (net.Conn, error) {
+	if t.DialTLS != nil {
+		return t.DialTLS
+	}
+	return t.dialTLSDefault
+}
+
+func (t *Transport) dialTLSDefault(network, addr string, cfg *tls.Config) (net.Conn, error) {
+	cn, err := tls.Dial(network, addr, cfg)
+	if err != nil {
+		return nil, err
+	}
+	if err := cn.Handshake(); err != nil {
+		return nil, err
+	}
+	if !cfg.InsecureSkipVerify {
+		if err := cn.VerifyHostname(cfg.ServerName); err != nil {
+			return nil, err
+		}
+	}
+	state := cn.ConnectionState()
+	if p := state.NegotiatedProtocol; p != NextProtoTLS {
+		return nil, fmt.Errorf("http2: unexpected ALPN protocol %q; want %q", p, NextProtoTLS)
+	}
+	if !state.NegotiatedProtocolIsMutual {
+		return nil, errors.New("http2: could not negotiate protocol mutually")
+	}
+	return cn, nil
+}
+
+// disableKeepAlives reports whether connections should be closed as
+// soon as possible after handling the first request.
+func (t *Transport) disableKeepAlives() bool {
+	return t.t1 != nil && t.t1.DisableKeepAlives
+}
+
+func (t *Transport) expectContinueTimeout() time.Duration {
+	if t.t1 == nil {
+		return 0
+	}
+	return transportExpectContinueTimeout(t.t1)
+}
+
+func (t *Transport) NewClientConn(c net.Conn) (*ClientConn, error) {
+	if VerboseLogs {
+		t.vlogf("http2: Transport creating client conn to %v", c.RemoteAddr())
+	}
+	if _, err := c.Write(clientPreface); err != nil {
+		t.vlogf("client preface write error: %v", err)
+		return nil, err
+	}
+
+	cc := &ClientConn{
+		t:                    t,
+		tconn:                c,
+		readerDone:           make(chan struct{}),
+		nextStreamID:         1,
+		maxFrameSize:         16 << 10, // spec default
+		initialWindowSize:    65535,    // spec default
+		maxConcurrentStreams: 1000,     // "infinite", per spec. 1000 seems good enough.
+		streams:              make(map[uint32]*clientStream),
+	}
+	cc.cond = sync.NewCond(&cc.mu)
+	cc.flow.add(int32(initialWindowSize))
+
+	// TODO: adjust this writer size to account for frame size +
+	// MTU + crypto/tls record padding.
+	cc.bw = bufio.NewWriter(stickyErrWriter{c, &cc.werr})
+	cc.br = bufio.NewReader(c)
+	cc.fr = NewFramer(cc.bw, cc.br)
+	cc.fr.ReadMetaHeaders = hpack.NewDecoder(initialHeaderTableSize, nil)
+	cc.fr.MaxHeaderListSize = t.maxHeaderListSize()
+
+	// TODO: SetMaxDynamicTableSize, SetMaxDynamicTableSizeLimit on
+	// henc in response to SETTINGS frames?
+	cc.henc = hpack.NewEncoder(&cc.hbuf)
+
+	if cs, ok := c.(connectionStater); ok {
+		state := cs.ConnectionState()
+		cc.tlsState = &state
+	}
+
+	initialSettings := []Setting{
+		{ID: SettingEnablePush, Val: 0},
+		{ID: SettingInitialWindowSize, Val: transportDefaultStreamFlow},
+	}
+	if max := t.maxHeaderListSize(); max != 0 {
+		initialSettings = append(initialSettings, Setting{ID: SettingMaxHeaderListSize, Val: max})
+	}
+	cc.fr.WriteSettings(initialSettings...)
+	cc.fr.WriteWindowUpdate(0, transportDefaultConnFlow)
+	cc.inflow.add(transportDefaultConnFlow + initialWindowSize)
+	cc.bw.Flush()
+	if cc.werr != nil {
+		return nil, cc.werr
+	}
+
+	// Read the obligatory SETTINGS frame
+	f, err := cc.fr.ReadFrame()
+	if err != nil {
+		return nil, err
+	}
+	sf, ok := f.(*SettingsFrame)
+	if !ok {
+		return nil, fmt.Errorf("expected settings frame, got: %T", f)
+	}
+	cc.fr.WriteSettingsAck()
+	cc.bw.Flush()
+
+	sf.ForeachSetting(func(s Setting) error {
+		switch s.ID {
+		case SettingMaxFrameSize:
+			cc.maxFrameSize = s.Val
+		case SettingMaxConcurrentStreams:
+			cc.maxConcurrentStreams = s.Val
+		case SettingInitialWindowSize:
+			cc.initialWindowSize = s.Val
+		default:
+			// TODO(bradfitz): handle more; at least SETTINGS_HEADER_TABLE_SIZE?
+			t.vlogf("Unhandled Setting: %v", s)
+		}
+		return nil
+	})
+
+	go cc.readLoop()
+	return cc, nil
+}
+
+func (cc *ClientConn) setGoAway(f *GoAwayFrame) {
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+	cc.goAway = f
+}
+
+func (cc *ClientConn) CanTakeNewRequest() bool {
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+	return cc.canTakeNewRequestLocked()
+}
+
+func (cc *ClientConn) canTakeNewRequestLocked() bool {
+	return cc.goAway == nil && !cc.closed &&
+		int64(len(cc.streams)+1) < int64(cc.maxConcurrentStreams) &&
+		cc.nextStreamID < 2147483647
+}
+
+func (cc *ClientConn) closeIfIdle() {
+	cc.mu.Lock()
+	if len(cc.streams) > 0 {
+		cc.mu.Unlock()
+		return
+	}
+	cc.closed = true
+	// TODO: do clients send GOAWAY too? maybe? Just Close:
+	cc.mu.Unlock()
+
+	cc.tconn.Close()
+}
+
+const maxAllocFrameSize = 512 << 10
+
+// frameBuffer returns a scratch buffer suitable for writing DATA frames.
+// They're capped at the min of the peer's max frame size or 512KB
+// (kinda arbitrarily), but definitely capped so we don't allocate 4GB
+// bufers.
+func (cc *ClientConn) frameScratchBuffer() []byte {
+	cc.mu.Lock()
+	size := cc.maxFrameSize
+	if size > maxAllocFrameSize {
+		size = maxAllocFrameSize
+	}
+	for i, buf := range cc.freeBuf {
+		if len(buf) >= int(size) {
+			cc.freeBuf[i] = nil
+			cc.mu.Unlock()
+			return buf[:size]
+		}
+	}
+	cc.mu.Unlock()
+	return make([]byte, size)
+}
+
+func (cc *ClientConn) putFrameScratchBuffer(buf []byte) {
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+	const maxBufs = 4 // arbitrary; 4 concurrent requests per conn? investigate.
+	if len(cc.freeBuf) < maxBufs {
+		cc.freeBuf = append(cc.freeBuf, buf)
+		return
+	}
+	for i, old := range cc.freeBuf {
+		if old == nil {
+			cc.freeBuf[i] = buf
+			return
+		}
+	}
+	// forget about it.
+}
+
+// errRequestCanceled is a copy of net/http's errRequestCanceled because it's not
+// exported. At least they'll be DeepEqual for h1-vs-h2 comparisons tests.
+var errRequestCanceled = errors.New("net/http: request canceled")
+
+func commaSeparatedTrailers(req *http.Request) (string, error) {
+	keys := make([]string, 0, len(req.Trailer))
+	for k := range req.Trailer {
+		k = http.CanonicalHeaderKey(k)
+		switch k {
+		case "Transfer-Encoding", "Trailer", "Content-Length":
+			return "", &badStringError{"invalid Trailer key", k}
+		}
+		keys = append(keys, k)
+	}
+	if len(keys) > 0 {
+		sort.Strings(keys)
+		// TODO: could do better allocation-wise here, but trailers are rare,
+		// so being lazy for now.
+		return strings.Join(keys, ","), nil
+	}
+	return "", nil
+}
+
+func (cc *ClientConn) responseHeaderTimeout() time.Duration {
+	if cc.t.t1 != nil {
+		return cc.t.t1.ResponseHeaderTimeout
+	}
+	// No way to do this (yet?) with just an http2.Transport. Probably
+	// no need. Request.Cancel this is the new way. We only need to support
+	// this for compatibility with the old http.Transport fields when
+	// we're doing transparent http2.
+	return 0
+}
+
+// checkConnHeaders checks whether req has any invalid connection-level headers.
+// per RFC 7540 section 8.1.2.2: Connection-Specific Header Fields.
+// Certain headers are special-cased as okay but not transmitted later.
+func checkConnHeaders(req *http.Request) error {
+	if v := req.Header.Get("Upgrade"); v != "" {
+		return errors.New("http2: invalid Upgrade request header")
+	}
+	if v := req.Header.Get("Transfer-Encoding"); (v != "" && v != "chunked") || len(req.Header["Transfer-Encoding"]) > 1 {
+		return errors.New("http2: invalid Transfer-Encoding request header")
+	}
+	if v := req.Header.Get("Connection"); (v != "" && v != "close" && v != "keep-alive") || len(req.Header["Connection"]) > 1 {
+		return errors.New("http2: invalid Connection request header")
+	}
+	return nil
+}
+
+func bodyAndLength(req *http.Request) (body io.Reader, contentLen int64) {
+	body = req.Body
+	if body == nil {
+		return nil, 0
+	}
+	if req.ContentLength != 0 {
+		return req.Body, req.ContentLength
+	}
+
+	// We have a body but a zero content length. Test to see if
+	// it's actually zero or just unset.
+	var buf [1]byte
+	n, rerr := io.ReadFull(body, buf[:])
+	if rerr != nil && rerr != io.EOF {
+		return errorReader{rerr}, -1
+	}
+	if n == 1 {
+		// Oh, guess there is data in this Body Reader after all.
+		// The ContentLength field just wasn't set.
+		// Stich the Body back together again, re-attaching our
+		// consumed byte.
+		return io.MultiReader(bytes.NewReader(buf[:]), body), -1
+	}
+	// Body is actually zero bytes.
+	return nil, 0
+}
+
+func (cc *ClientConn) RoundTrip(req *http.Request) (*http.Response, error) {
+	if err := checkConnHeaders(req); err != nil {
+		return nil, err
+	}
+
+	trailers, err := commaSeparatedTrailers(req)
+	if err != nil {
+		return nil, err
+	}
+	hasTrailers := trailers != ""
+
+	body, contentLen := bodyAndLength(req)
+	hasBody := body != nil
+
+	cc.mu.Lock()
+	cc.lastActive = time.Now()
+	if cc.closed || !cc.canTakeNewRequestLocked() {
+		cc.mu.Unlock()
+		return nil, errClientConnUnusable
+	}
+
+	// TODO(bradfitz): this is a copy of the logic in net/http. Unify somewhere?
+	var requestedGzip bool
+	if !cc.t.disableCompression() &&
+		req.Header.Get("Accept-Encoding") == "" &&
+		req.Header.Get("Range") == "" &&
+		req.Method != "HEAD" {
+		// Request gzip only, not deflate. Deflate is ambiguous and
+		// not as universally supported anyway.
+		// See: http://www.gzip.org/zlib/zlib_faq.html#faq38
+		//
+		// Note that we don't request this for HEAD requests,
+		// due to a bug in nginx:
+		//   http://trac.nginx.org/nginx/ticket/358
+		//   https://golang.org/issue/5522
+		//
+		// We don't request gzip if the request is for a range, since
+		// auto-decoding a portion of a gzipped document will just fail
+		// anyway. See https://golang.org/issue/8923
+		requestedGzip = true
+	}
+
+	// we send: HEADERS{1}, CONTINUATION{0,} + DATA{0,} (DATA is
+	// sent by writeRequestBody below, along with any Trailers,
+	// again in form HEADERS{1}, CONTINUATION{0,})
+	hdrs, err := cc.encodeHeaders(req, requestedGzip, trailers, contentLen)
+	if err != nil {
+		cc.mu.Unlock()
+		return nil, err
+	}
+
+	cs := cc.newStream()
+	cs.req = req
+	cs.trace = requestTrace(req)
+	cs.requestedGzip = requestedGzip
+	bodyWriter := cc.t.getBodyWriterState(cs, body)
+	cs.on100 = bodyWriter.on100
+
+	cc.wmu.Lock()
+	endStream := !hasBody && !hasTrailers
+	werr := cc.writeHeaders(cs.ID, endStream, hdrs)
+	cc.wmu.Unlock()
+	traceWroteHeaders(cs.trace)
+	cc.mu.Unlock()
+
+	if werr != nil {
+		if hasBody {
+			req.Body.Close() // per RoundTripper contract
+			bodyWriter.cancel()
+		}
+		cc.forgetStreamID(cs.ID)
+		// Don't bother sending a RST_STREAM (our write already failed;
+		// no need to keep writing)
+		traceWroteRequest(cs.trace, werr)
+		return nil, werr
+	}
+
+	var respHeaderTimer <-chan time.Time
+	if hasBody {
+		bodyWriter.scheduleBodyWrite()
+	} else {
+		traceWroteRequest(cs.trace, nil)
+		if d := cc.responseHeaderTimeout(); d != 0 {
+			timer := time.NewTimer(d)
+			defer timer.Stop()
+			respHeaderTimer = timer.C
+		}
+	}
+
+	readLoopResCh := cs.resc
+	bodyWritten := false
+	ctx := reqContext(req)
+
+	for {
+		select {
+		case re := <-readLoopResCh:
+			res := re.res
+			if re.err != nil || res.StatusCode > 299 {
+				// On error or status code 3xx, 4xx, 5xx, etc abort any
+				// ongoing write, assuming that the server doesn't care
+				// about our request body. If the server replied with 1xx or
+				// 2xx, however, then assume the server DOES potentially
+				// want our body (e.g. full-duplex streaming:
+				// golang.org/issue/13444). If it turns out the server
+				// doesn't, they'll RST_STREAM us soon enough.  This is a
+				// heuristic to avoid adding knobs to Transport.  Hopefully
+				// we can keep it.
+				bodyWriter.cancel()
+				cs.abortRequestBodyWrite(errStopReqBodyWrite)
+			}
+			if re.err != nil {
+				cc.forgetStreamID(cs.ID)
+				return nil, re.err
+			}
+			res.Request = req
+			res.TLS = cc.tlsState
+			return res, nil
+		case <-respHeaderTimer:
+			cc.forgetStreamID(cs.ID)
+			if !hasBody || bodyWritten {
+				cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
+			} else {
+				bodyWriter.cancel()
+				cs.abortRequestBodyWrite(errStopReqBodyWriteAndCancel)
+			}
+			return nil, errTimeout
+		case <-ctx.Done():
+			cc.forgetStreamID(cs.ID)
+			if !hasBody || bodyWritten {
+				cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
+			} else {
+				bodyWriter.cancel()
+				cs.abortRequestBodyWrite(errStopReqBodyWriteAndCancel)
+			}
+			return nil, ctx.Err()
+		case <-req.Cancel:
+			cc.forgetStreamID(cs.ID)
+			if !hasBody || bodyWritten {
+				cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
+			} else {
+				bodyWriter.cancel()
+				cs.abortRequestBodyWrite(errStopReqBodyWriteAndCancel)
+			}
+			return nil, errRequestCanceled
+		case <-cs.peerReset:
+			// processResetStream already removed the
+			// stream from the streams map; no need for
+			// forgetStreamID.
+			return nil, cs.resetErr
+		case err := <-bodyWriter.resc:
+			if err != nil {
+				return nil, err
+			}
+			bodyWritten = true
+			if d := cc.responseHeaderTimeout(); d != 0 {
+				timer := time.NewTimer(d)
+				defer timer.Stop()
+				respHeaderTimer = timer.C
+			}
+		}
+	}
+}
+
+// requires cc.wmu be held
+func (cc *ClientConn) writeHeaders(streamID uint32, endStream bool, hdrs []byte) error {
+	first := true // first frame written (HEADERS is first, then CONTINUATION)
+	frameSize := int(cc.maxFrameSize)
+	for len(hdrs) > 0 && cc.werr == nil {
+		chunk := hdrs
+		if len(chunk) > frameSize {
+			chunk = chunk[:frameSize]
+		}
+		hdrs = hdrs[len(chunk):]
+		endHeaders := len(hdrs) == 0
+		if first {
+			cc.fr.WriteHeaders(HeadersFrameParam{
+				StreamID:      streamID,
+				BlockFragment: chunk,
+				EndStream:     endStream,
+				EndHeaders:    endHeaders,
+			})
+			first = false
+		} else {
+			cc.fr.WriteContinuation(streamID, endHeaders, chunk)
+		}
+	}
+	// TODO(bradfitz): this Flush could potentially block (as
+	// could the WriteHeaders call(s) above), which means they
+	// wouldn't respond to Request.Cancel being readable. That's
+	// rare, but this should probably be in a goroutine.
+	cc.bw.Flush()
+	return cc.werr
+}
+
+// internal error values; they don't escape to callers
+var (
+	// abort request body write; don't send cancel
+	errStopReqBodyWrite = errors.New("http2: aborting request body write")
+
+	// abort request body write, but send stream reset of cancel.
+	errStopReqBodyWriteAndCancel = errors.New("http2: canceling request")
+)
+
+func (cs *clientStream) writeRequestBody(body io.Reader, bodyCloser io.Closer) (err error) {
+	cc := cs.cc
+	sentEnd := false // whether we sent the final DATA frame w/ END_STREAM
+	buf := cc.frameScratchBuffer()
+	defer cc.putFrameScratchBuffer(buf)
+
+	defer func() {
+		traceWroteRequest(cs.trace, err)
+		// TODO: write h12Compare test showing whether
+		// Request.Body is closed by the Transport,
+		// and in multiple cases: server replies <=299 and >299
+		// while still writing request body
+		cerr := bodyCloser.Close()
+		if err == nil {
+			err = cerr
+		}
+	}()
+
+	req := cs.req
+	hasTrailers := req.Trailer != nil
+
+	var sawEOF bool
+	for !sawEOF {
+		n, err := body.Read(buf)
+		if err == io.EOF {
+			sawEOF = true
+			err = nil
+		} else if err != nil {
+			return err
+		}
+
+		remain := buf[:n]
+		for len(remain) > 0 && err == nil {
+			var allowed int32
+			allowed, err = cs.awaitFlowControl(len(remain))
+			switch {
+			case err == errStopReqBodyWrite:
+				return err
+			case err == errStopReqBodyWriteAndCancel:
+				cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
+				return err
+			case err != nil:
+				return err
+			}
+			cc.wmu.Lock()
+			data := remain[:allowed]
+			remain = remain[allowed:]
+			sentEnd = sawEOF && len(remain) == 0 && !hasTrailers
+			err = cc.fr.WriteData(cs.ID, sentEnd, data)
+			if err == nil {
+				// TODO(bradfitz): this flush is for latency, not bandwidth.
+				// Most requests won't need this. Make this opt-in or opt-out?
+				// Use some heuristic on the body type? Nagel-like timers?
+				// Based on 'n'? Only last chunk of this for loop, unless flow control
+				// tokens are low? For now, always:
+				err = cc.bw.Flush()
+			}
+			cc.wmu.Unlock()
+		}
+		if err != nil {
+			return err
+		}
+	}
+
+	cc.wmu.Lock()
+	if !sentEnd {
+		var trls []byte
+		if hasTrailers {
+			cc.mu.Lock()
+			trls = cc.encodeTrailers(req)
+			cc.mu.Unlock()
+		}
+
+		// Avoid forgetting to send an END_STREAM if the encoded
+		// trailers are 0 bytes. Both results produce and END_STREAM.
+		if len(trls) > 0 {
+			err = cc.writeHeaders(cs.ID, true, trls)
+		} else {
+			err = cc.fr.WriteData(cs.ID, true, nil)
+		}
+	}
+	if ferr := cc.bw.Flush(); ferr != nil && err == nil {
+		err = ferr
+	}
+	cc.wmu.Unlock()
+
+	return err
+}
+
+// awaitFlowControl waits for [1, min(maxBytes, cc.cs.maxFrameSize)] flow
+// control tokens from the server.
+// It returns either the non-zero number of tokens taken or an error
+// if the stream is dead.
+func (cs *clientStream) awaitFlowControl(maxBytes int) (taken int32, err error) {
+	cc := cs.cc
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+	for {
+		if cc.closed {
+			return 0, errClientConnClosed
+		}
+		if cs.stopReqBody != nil {
+			return 0, cs.stopReqBody
+		}
+		if err := cs.checkResetOrDone(); err != nil {
+			return 0, err
+		}
+		if a := cs.flow.available(); a > 0 {
+			take := a
+			if int(take) > maxBytes {
+
+				take = int32(maxBytes) // can't truncate int; take is int32
+			}
+			if take > int32(cc.maxFrameSize) {
+				take = int32(cc.maxFrameSize)
+			}
+			cs.flow.take(take)
+			return take, nil
+		}
+		cc.cond.Wait()
+	}
+}
+
+type badStringError struct {
+	what string
+	str  string
+}
+
+func (e *badStringError) Error() string { return fmt.Sprintf("%s %q", e.what, e.str) }
+
+// requires cc.mu be held.
+func (cc *ClientConn) encodeHeaders(req *http.Request, addGzipHeader bool, trailers string, contentLength int64) ([]byte, error) {
+	cc.hbuf.Reset()
+
+	host := req.Host
+	if host == "" {
+		host = req.URL.Host
+	}
+
+	// Check for any invalid headers and return an error before we
+	// potentially pollute our hpack state. (We want to be able to
+	// continue to reuse the hpack encoder for future requests)
+	for k, vv := range req.Header {
+		if !httplex.ValidHeaderFieldName(k) {
+			return nil, fmt.Errorf("invalid HTTP header name %q", k)
+		}
+		for _, v := range vv {
+			if !httplex.ValidHeaderFieldValue(v) {
+				return nil, fmt.Errorf("invalid HTTP header value %q for header %q", v, k)
+			}
+		}
+	}
+
+	// 8.1.2.3 Request Pseudo-Header Fields
+	// The :path pseudo-header field includes the path and query parts of the
+	// target URI (the path-absolute production and optionally a '?' character
+	// followed by the query production (see Sections 3.3 and 3.4 of
+	// [RFC3986]).
+	cc.writeHeader(":authority", host)
+	cc.writeHeader(":method", req.Method)
+	if req.Method != "CONNECT" {
+		cc.writeHeader(":path", req.URL.RequestURI())
+		cc.writeHeader(":scheme", "https")
+	}
+	if trailers != "" {
+		cc.writeHeader("trailer", trailers)
+	}
+
+	var didUA bool
+	for k, vv := range req.Header {
+		lowKey := strings.ToLower(k)
+		switch lowKey {
+		case "host", "content-length":
+			// Host is :authority, already sent.
+			// Content-Length is automatic, set below.
+			continue
+		case "connection", "proxy-connection", "transfer-encoding", "upgrade", "keep-alive":
+			// Per 8.1.2.2 Connection-Specific Header
+			// Fields, don't send connection-specific
+			// fields. We have already checked if any
+			// are error-worthy so just ignore the rest.
+			continue
+		case "user-agent":
+			// Match Go's http1 behavior: at most one
+			// User-Agent. If set to nil or empty string,
+			// then omit it. Otherwise if not mentioned,
+			// include the default (below).
+			didUA = true
+			if len(vv) < 1 {
+				continue
+			}
+			vv = vv[:1]
+			if vv[0] == "" {
+				continue
+			}
+		}
+		for _, v := range vv {
+			cc.writeHeader(lowKey, v)
+		}
+	}
+	if shouldSendReqContentLength(req.Method, contentLength) {
+		cc.writeHeader("content-length", strconv.FormatInt(contentLength, 10))
+	}
+	if addGzipHeader {
+		cc.writeHeader("accept-encoding", "gzip")
+	}
+	if !didUA {
+		cc.writeHeader("user-agent", defaultUserAgent)
+	}
+	return cc.hbuf.Bytes(), nil
+}
+
+// shouldSendReqContentLength reports whether the http2.Transport should send
+// a "content-length" request header. This logic is basically a copy of the net/http
+// transferWriter.shouldSendContentLength.
+// The contentLength is the corrected contentLength (so 0 means actually 0, not unknown).
+// -1 means unknown.
+func shouldSendReqContentLength(method string, contentLength int64) bool {
+	if contentLength > 0 {
+		return true
+	}
+	if contentLength < 0 {
+		return false
+	}
+	// For zero bodies, whether we send a content-length depends on the method.
+	// It also kinda doesn't matter for http2 either way, with END_STREAM.
+	switch method {
+	case "POST", "PUT", "PATCH":
+		return true
+	default:
+		return false
+	}
+}
+
+// requires cc.mu be held.
+func (cc *ClientConn) encodeTrailers(req *http.Request) []byte {
+	cc.hbuf.Reset()
+	for k, vv := range req.Trailer {
+		// Transfer-Encoding, etc.. have already been filter at the
+		// start of RoundTrip
+		lowKey := strings.ToLower(k)
+		for _, v := range vv {
+			cc.writeHeader(lowKey, v)
+		}
+	}
+	return cc.hbuf.Bytes()
+}
+
+func (cc *ClientConn) writeHeader(name, value string) {
+	if VerboseLogs {
+		log.Printf("http2: Transport encoding header %q = %q", name, value)
+	}
+	cc.henc.WriteField(hpack.HeaderField{Name: name, Value: value})
+}
+
+type resAndError struct {
+	res *http.Response
+	err error
+}
+
+// requires cc.mu be held.
+func (cc *ClientConn) newStream() *clientStream {
+	cs := &clientStream{
+		cc:        cc,
+		ID:        cc.nextStreamID,
+		resc:      make(chan resAndError, 1),
+		peerReset: make(chan struct{}),
+		done:      make(chan struct{}),
+	}
+	cs.flow.add(int32(cc.initialWindowSize))
+	cs.flow.setConnFlow(&cc.flow)
+	cs.inflow.add(transportDefaultStreamFlow)
+	cs.inflow.setConnFlow(&cc.inflow)
+	cc.nextStreamID += 2
+	cc.streams[cs.ID] = cs
+	return cs
+}
+
+func (cc *ClientConn) forgetStreamID(id uint32) {
+	cc.streamByID(id, true)
+}
+
+func (cc *ClientConn) streamByID(id uint32, andRemove bool) *clientStream {
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+	cs := cc.streams[id]
+	if andRemove && cs != nil && !cc.closed {
+		cc.lastActive = time.Now()
+		delete(cc.streams, id)
+		close(cs.done)
+		cc.cond.Broadcast() // wake up checkResetOrDone via clientStream.awaitFlowControl
+	}
+	return cs
+}
+
+// clientConnReadLoop is the state owned by the clientConn's frame-reading readLoop.
+type clientConnReadLoop struct {
+	cc            *ClientConn
+	activeRes     map[uint32]*clientStream // keyed by streamID
+	closeWhenIdle bool
+}
+
+// readLoop runs in its own goroutine and reads and dispatches frames.
+func (cc *ClientConn) readLoop() {
+	rl := &clientConnReadLoop{
+		cc:        cc,
+		activeRes: make(map[uint32]*clientStream),
+	}
+
+	defer rl.cleanup()
+	cc.readerErr = rl.run()
+	if ce, ok := cc.readerErr.(ConnectionError); ok {
+		cc.wmu.Lock()
+		cc.fr.WriteGoAway(0, ErrCode(ce), nil)
+		cc.wmu.Unlock()
+	}
+}
+
+func (rl *clientConnReadLoop) cleanup() {
+	cc := rl.cc
+	defer cc.tconn.Close()
+	defer cc.t.connPool().MarkDead(cc)
+	defer close(cc.readerDone)
+
+	// Close any response bodies if the server closes prematurely.
+	// TODO: also do this if we've written the headers but not
+	// gotten a response yet.
+	err := cc.readerErr
+	if err == io.EOF {
+		err = io.ErrUnexpectedEOF
+	}
+	cc.mu.Lock()
+	for _, cs := range rl.activeRes {
+		cs.bufPipe.CloseWithError(err)
+	}
+	for _, cs := range cc.streams {
+		select {
+		case cs.resc <- resAndError{err: err}:
+		default:
+		}
+		close(cs.done)
+	}
+	cc.closed = true
+	cc.cond.Broadcast()
+	cc.mu.Unlock()
+}
+
+func (rl *clientConnReadLoop) run() error {
+	cc := rl.cc
+	rl.closeWhenIdle = cc.t.disableKeepAlives()
+	gotReply := false // ever saw a reply
+	for {
+		f, err := cc.fr.ReadFrame()
+		if err != nil {
+			cc.vlogf("Transport readFrame error: (%T) %v", err, err)
+		}
+		if se, ok := err.(StreamError); ok {
+			if cs := cc.streamByID(se.StreamID, true /*ended; remove it*/); cs != nil {
+				rl.endStreamError(cs, cc.fr.errDetail)
+			}
+			continue
+		} else if err != nil {
+			return err
+		}
+		if VerboseLogs {
+			cc.vlogf("http2: Transport received %s", summarizeFrame(f))
+		}
+		maybeIdle := false // whether frame might transition us to idle
+
+		switch f := f.(type) {
+		case *MetaHeadersFrame:
+			err = rl.processHeaders(f)
+			maybeIdle = true
+			gotReply = true
+		case *DataFrame:
+			err = rl.processData(f)
+			maybeIdle = true
+		case *GoAwayFrame:
+			err = rl.processGoAway(f)
+			maybeIdle = true
+		case *RSTStreamFrame:
+			err = rl.processResetStream(f)
+			maybeIdle = true
+		case *SettingsFrame:
+			err = rl.processSettings(f)
+		case *PushPromiseFrame:
+			err = rl.processPushPromise(f)
+		case *WindowUpdateFrame:
+			err = rl.processWindowUpdate(f)
+		case *PingFrame:
+			err = rl.processPing(f)
+		default:
+			cc.logf("Transport: unhandled response frame type %T", f)
+		}
+		if err != nil {
+			return err
+		}
+		if rl.closeWhenIdle && gotReply && maybeIdle && len(rl.activeRes) == 0 {
+			cc.closeIfIdle()
+		}
+	}
+}
+
+func (rl *clientConnReadLoop) processHeaders(f *MetaHeadersFrame) error {
+	cc := rl.cc
+	cs := cc.streamByID(f.StreamID, f.StreamEnded())
+	if cs == nil {
+		// We'd get here if we canceled a request while the
+		// server had its response still in flight. So if this
+		// was just something we canceled, ignore it.
+		return nil
+	}
+	if !cs.pastHeaders {
+		cs.pastHeaders = true
+	} else {
+		return rl.processTrailers(cs, f)
+	}
+	if cs.trace != nil {
+		// TODO(bradfitz): move first response byte earlier,
+		// when we first read the 9 byte header, not waiting
+		// until all the HEADERS+CONTINUATION frames have been
+		// merged. This works for now.
+		traceFirstResponseByte(cs.trace)
+	}
+
+	res, err := rl.handleResponse(cs, f)
+	if err != nil {
+		if _, ok := err.(ConnectionError); ok {
+			return err
+		}
+		// Any other error type is a stream error.
+		cs.cc.writeStreamReset(f.StreamID, ErrCodeProtocol, err)
+		cs.resc <- resAndError{err: err}
+		return nil // return nil from process* funcs to keep conn alive
+	}
+	if res == nil {
+		// (nil, nil) special case. See handleResponse docs.
+		return nil
+	}
+	if res.Body != noBody {
+		rl.activeRes[cs.ID] = cs
+	}
+	cs.resTrailer = &res.Trailer
+	cs.resc <- resAndError{res: res}
+	return nil
+}
+
+// may return error types nil, or ConnectionError. Any other error value
+// is a StreamError of type ErrCodeProtocol. The returned error in that case
+// is the detail.
+//
+// As a special case, handleResponse may return (nil, nil) to skip the
+// frame (currently only used for 100 expect continue). This special
+// case is going away after Issue 13851 is fixed.
+func (rl *clientConnReadLoop) handleResponse(cs *clientStream, f *MetaHeadersFrame) (*http.Response, error) {
+	if f.Truncated {
+		return nil, errResponseHeaderListSize
+	}
+
+	status := f.PseudoValue("status")
+	if status == "" {
+		return nil, errors.New("missing status pseudo header")
+	}
+	statusCode, err := strconv.Atoi(status)
+	if err != nil {
+		return nil, errors.New("malformed non-numeric status pseudo header")
+	}
+
+	if statusCode == 100 {
+		traceGot100Continue(cs.trace)
+		if cs.on100 != nil {
+			cs.on100() // forces any write delay timer to fire
+		}
+		cs.pastHeaders = false // do it all again
+		return nil, nil
+	}
+
+	header := make(http.Header)
+	res := &http.Response{
+		Proto:      "HTTP/2.0",
+		ProtoMajor: 2,
+		Header:     header,
+		StatusCode: statusCode,
+		Status:     status + " " + http.StatusText(statusCode),
+	}
+	for _, hf := range f.RegularFields() {
+		key := http.CanonicalHeaderKey(hf.Name)
+		if key == "Trailer" {
+			t := res.Trailer
+			if t == nil {
+				t = make(http.Header)
+				res.Trailer = t
+			}
+			foreachHeaderElement(hf.Value, func(v string) {
+				t[http.CanonicalHeaderKey(v)] = nil
+			})
+		} else {
+			header[key] = append(header[key], hf.Value)
+		}
+	}
+
+	streamEnded := f.StreamEnded()
+	isHead := cs.req.Method == "HEAD"
+	if !streamEnded || isHead {
+		res.ContentLength = -1
+		if clens := res.Header["Content-Length"]; len(clens) == 1 {
+			if clen64, err := strconv.ParseInt(clens[0], 10, 64); err == nil {
+				res.ContentLength = clen64
+			} else {
+				// TODO: care? unlike http/1, it won't mess up our framing, so it's
+				// more safe smuggling-wise to ignore.
+			}
+		} else if len(clens) > 1 {
+			// TODO: care? unlike http/1, it won't mess up our framing, so it's
+			// more safe smuggling-wise to ignore.
+		}
+	}
+
+	if streamEnded || isHead {
+		res.Body = noBody
+		return res, nil
+	}
+
+	buf := new(bytes.Buffer) // TODO(bradfitz): recycle this garbage
+	cs.bufPipe = pipe{b: buf}
+	cs.bytesRemain = res.ContentLength
+	res.Body = transportResponseBody{cs}
+	go cs.awaitRequestCancel(cs.req)
+
+	if cs.requestedGzip && res.Header.Get("Content-Encoding") == "gzip" {
+		res.Header.Del("Content-Encoding")
+		res.Header.Del("Content-Length")
+		res.ContentLength = -1
+		res.Body = &gzipReader{body: res.Body}
+		setResponseUncompressed(res)
+	}
+	return res, nil
+}
+
+func (rl *clientConnReadLoop) processTrailers(cs *clientStream, f *MetaHeadersFrame) error {
+	if cs.pastTrailers {
+		// Too many HEADERS frames for this stream.
+		return ConnectionError(ErrCodeProtocol)
+	}
+	cs.pastTrailers = true
+	if !f.StreamEnded() {
+		// We expect that any headers for trailers also
+		// has END_STREAM.
+		return ConnectionError(ErrCodeProtocol)
+	}
+	if len(f.PseudoFields()) > 0 {
+		// No pseudo header fields are defined for trailers.
+		// TODO: ConnectionError might be overly harsh? Check.
+		return ConnectionError(ErrCodeProtocol)
+	}
+
+	trailer := make(http.Header)
+	for _, hf := range f.RegularFields() {
+		key := http.CanonicalHeaderKey(hf.Name)
+		trailer[key] = append(trailer[key], hf.Value)
+	}
+	cs.trailer = trailer
+
+	rl.endStream(cs)
+	return nil
+}
+
+// transportResponseBody is the concrete type of Transport.RoundTrip's
+// Response.Body. It is an io.ReadCloser. On Read, it reads from cs.body.
+// On Close it sends RST_STREAM if EOF wasn't already seen.
+type transportResponseBody struct {
+	cs *clientStream
+}
+
+func (b transportResponseBody) Read(p []byte) (n int, err error) {
+	cs := b.cs
+	cc := cs.cc
+
+	if cs.readErr != nil {
+		return 0, cs.readErr
+	}
+	n, err = b.cs.bufPipe.Read(p)
+	if cs.bytesRemain != -1 {
+		if int64(n) > cs.bytesRemain {
+			n = int(cs.bytesRemain)
+			if err == nil {
+				err = errors.New("net/http: server replied with more than declared Content-Length; truncated")
+				cc.writeStreamReset(cs.ID, ErrCodeProtocol, err)
+			}
+			cs.readErr = err
+			return int(cs.bytesRemain), err
+		}
+		cs.bytesRemain -= int64(n)
+		if err == io.EOF && cs.bytesRemain > 0 {
+			err = io.ErrUnexpectedEOF
+			cs.readErr = err
+			return n, err
+		}
+	}
+	if n == 0 {
+		// No flow control tokens to send back.
+		return
+	}
+
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+
+	var connAdd, streamAdd int32
+	// Check the conn-level first, before the stream-level.
+	if v := cc.inflow.available(); v < transportDefaultConnFlow/2 {
+		connAdd = transportDefaultConnFlow - v
+		cc.inflow.add(connAdd)
+	}
+	if err == nil { // No need to refresh if the stream is over or failed.
+		if v := cs.inflow.available(); v < transportDefaultStreamFlow-transportDefaultStreamMinRefresh {
+			streamAdd = transportDefaultStreamFlow - v
+			cs.inflow.add(streamAdd)
+		}
+	}
+	if connAdd != 0 || streamAdd != 0 {
+		cc.wmu.Lock()
+		defer cc.wmu.Unlock()
+		if connAdd != 0 {
+			cc.fr.WriteWindowUpdate(0, mustUint31(connAdd))
+		}
+		if streamAdd != 0 {
+			cc.fr.WriteWindowUpdate(cs.ID, mustUint31(streamAdd))
+		}
+		cc.bw.Flush()
+	}
+	return
+}
+
+var errClosedResponseBody = errors.New("http2: response body closed")
+
+func (b transportResponseBody) Close() error {
+	cs := b.cs
+	if cs.bufPipe.Err() != io.EOF {
+		// TODO: write test for this
+		cs.cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
+	}
+	cs.bufPipe.BreakWithError(errClosedResponseBody)
+	return nil
+}
+
+func (rl *clientConnReadLoop) processData(f *DataFrame) error {
+	cc := rl.cc
+	cs := cc.streamByID(f.StreamID, f.StreamEnded())
+	if cs == nil {
+		cc.mu.Lock()
+		neverSent := cc.nextStreamID
+		cc.mu.Unlock()
+		if f.StreamID >= neverSent {
+			// We never asked for this.
+			cc.logf("http2: Transport received unsolicited DATA frame; closing connection")
+			return ConnectionError(ErrCodeProtocol)
+		}
+		// We probably did ask for this, but canceled. Just ignore it.
+		// TODO: be stricter here? only silently ignore things which
+		// we canceled, but not things which were closed normally
+		// by the peer? Tough without accumulating too much state.
+		return nil
+	}
+	if data := f.Data(); len(data) > 0 {
+		if cs.bufPipe.b == nil {
+			// Data frame after it's already closed?
+			cc.logf("http2: Transport received DATA frame for closed stream; closing connection")
+			return ConnectionError(ErrCodeProtocol)
+		}
+
+		// Check connection-level flow control.
+		cc.mu.Lock()
+		if cs.inflow.available() >= int32(len(data)) {
+			cs.inflow.take(int32(len(data)))
+		} else {
+			cc.mu.Unlock()
+			return ConnectionError(ErrCodeFlowControl)
+		}
+		cc.mu.Unlock()
+
+		if _, err := cs.bufPipe.Write(data); err != nil {
+			rl.endStreamError(cs, err)
+			return err
+		}
+	}
+
+	if f.StreamEnded() {
+		rl.endStream(cs)
+	}
+	return nil
+}
+
+var errInvalidTrailers = errors.New("http2: invalid trailers")
+
+func (rl *clientConnReadLoop) endStream(cs *clientStream) {
+	// TODO: check that any declared content-length matches, like
+	// server.go's (*stream).endStream method.
+	rl.endStreamError(cs, nil)
+}
+
+func (rl *clientConnReadLoop) endStreamError(cs *clientStream, err error) {
+	var code func()
+	if err == nil {
+		err = io.EOF
+		code = cs.copyTrailers
+	}
+	cs.bufPipe.closeWithErrorAndCode(err, code)
+	delete(rl.activeRes, cs.ID)
+	if cs.req.Close || cs.req.Header.Get("Connection") == "close" {
+		rl.closeWhenIdle = true
+	}
+}
+
+func (cs *clientStream) copyTrailers() {
+	for k, vv := range cs.trailer {
+		t := cs.resTrailer
+		if *t == nil {
+			*t = make(http.Header)
+		}
+		(*t)[k] = vv
+	}
+}
+
+func (rl *clientConnReadLoop) processGoAway(f *GoAwayFrame) error {
+	cc := rl.cc
+	cc.t.connPool().MarkDead(cc)
+	if f.ErrCode != 0 {
+		// TODO: deal with GOAWAY more. particularly the error code
+		cc.vlogf("transport got GOAWAY with error code = %v", f.ErrCode)
+	}
+	cc.setGoAway(f)
+	return nil
+}
+
+func (rl *clientConnReadLoop) processSettings(f *SettingsFrame) error {
+	cc := rl.cc
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+	return f.ForeachSetting(func(s Setting) error {
+		switch s.ID {
+		case SettingMaxFrameSize:
+			cc.maxFrameSize = s.Val
+		case SettingMaxConcurrentStreams:
+			cc.maxConcurrentStreams = s.Val
+		case SettingInitialWindowSize:
+			// TODO: error if this is too large.
+
+			// TODO: adjust flow control of still-open
+			// frames by the difference of the old initial
+			// window size and this one.
+			cc.initialWindowSize = s.Val
+		default:
+			// TODO(bradfitz): handle more settings? SETTINGS_HEADER_TABLE_SIZE probably.
+			cc.vlogf("Unhandled Setting: %v", s)
+		}
+		return nil
+	})
+}
+
+func (rl *clientConnReadLoop) processWindowUpdate(f *WindowUpdateFrame) error {
+	cc := rl.cc
+	cs := cc.streamByID(f.StreamID, false)
+	if f.StreamID != 0 && cs == nil {
+		return nil
+	}
+
+	cc.mu.Lock()
+	defer cc.mu.Unlock()
+
+	fl := &cc.flow
+	if cs != nil {
+		fl = &cs.flow
+	}
+	if !fl.add(int32(f.Increment)) {
+		return ConnectionError(ErrCodeFlowControl)
+	}
+	cc.cond.Broadcast()
+	return nil
+}
+
+func (rl *clientConnReadLoop) processResetStream(f *RSTStreamFrame) error {
+	cs := rl.cc.streamByID(f.StreamID, true)
+	if cs == nil {
+		// TODO: return error if server tries to RST_STEAM an idle stream
+		return nil
+	}
+	select {
+	case <-cs.peerReset:
+		// Already reset.
+		// This is the only goroutine
+		// which closes this, so there
+		// isn't a race.
+	default:
+		err := StreamError{cs.ID, f.ErrCode}
+		cs.resetErr = err
+		close(cs.peerReset)
+		cs.bufPipe.CloseWithError(err)
+		cs.cc.cond.Broadcast() // wake up checkResetOrDone via clientStream.awaitFlowControl
+	}
+	delete(rl.activeRes, cs.ID)
+	return nil
+}
+
+func (rl *clientConnReadLoop) processPing(f *PingFrame) error {
+	if f.IsAck() {
+		// 6.7 PING: " An endpoint MUST NOT respond to PING frames
+		// containing this flag."
+		return nil
+	}
+	cc := rl.cc
+	cc.wmu.Lock()
+	defer cc.wmu.Unlock()
+	if err := cc.fr.WritePing(true, f.Data); err != nil {
+		return err
+	}
+	return cc.bw.Flush()
+}
+
+func (rl *clientConnReadLoop) processPushPromise(f *PushPromiseFrame) error {
+	// We told the peer we don't want them.
+	// Spec says:
+	// "PUSH_PROMISE MUST NOT be sent if the SETTINGS_ENABLE_PUSH
+	// setting of the peer endpoint is set to 0. An endpoint that
+	// has set this setting and has received acknowledgement MUST
+	// treat the receipt of a PUSH_PROMISE frame as a connection
+	// error (Section 5.4.1) of type PROTOCOL_ERROR."
+	return ConnectionError(ErrCodeProtocol)
+}
+
+func (cc *ClientConn) writeStreamReset(streamID uint32, code ErrCode, err error) {
+	// TODO: do something with err? send it as a debug frame to the peer?
+	// But that's only in GOAWAY. Invent a new frame type? Is there one already?
+	cc.wmu.Lock()
+	cc.fr.WriteRSTStream(streamID, code)
+	cc.bw.Flush()
+	cc.wmu.Unlock()
+}
+
+var (
+	errResponseHeaderListSize = errors.New("http2: response header list larger than advertised limit")
+	errPseudoTrailers         = errors.New("http2: invalid pseudo header in trailers")
+)
+
+func (cc *ClientConn) logf(format string, args ...interface{}) {
+	cc.t.logf(format, args...)
+}
+
+func (cc *ClientConn) vlogf(format string, args ...interface{}) {
+	cc.t.vlogf(format, args...)
+}
+
+func (t *Transport) vlogf(format string, args ...interface{}) {
+	if VerboseLogs {
+		t.logf(format, args...)
+	}
+}
+
+func (t *Transport) logf(format string, args ...interface{}) {
+	log.Printf(format, args...)
+}
+
+var noBody io.ReadCloser = ioutil.NopCloser(bytes.NewReader(nil))
+
+func strSliceContains(ss []string, s string) bool {
+	for _, v := range ss {
+		if v == s {
+			return true
+		}
+	}
+	return false
+}
+
+type erringRoundTripper struct{ err error }
+
+func (rt erringRoundTripper) RoundTrip(*http.Request) (*http.Response, error) { return nil, rt.err }
+
+// gzipReader wraps a response body so it can lazily
+// call gzip.NewReader on the first call to Read
+type gzipReader struct {
+	body io.ReadCloser // underlying Response.Body
+	zr   *gzip.Reader  // lazily-initialized gzip reader
+	zerr error         // sticky error
+}
+
+func (gz *gzipReader) Read(p []byte) (n int, err error) {
+	if gz.zerr != nil {
+		return 0, gz.zerr
+	}
+	if gz.zr == nil {
+		gz.zr, err = gzip.NewReader(gz.body)
+		if err != nil {
+			gz.zerr = err
+			return 0, err
+		}
+	}
+	return gz.zr.Read(p)
+}
+
+func (gz *gzipReader) Close() error {
+	return gz.body.Close()
+}
+
+type errorReader struct{ err error }
+
+func (r errorReader) Read(p []byte) (int, error) { return 0, r.err }
+
+// bodyWriterState encapsulates various state around the Transport's writing
+// of the request body, particularly regarding doing delayed writes of the body
+// when the request contains "Expect: 100-continue".
+type bodyWriterState struct {
+	cs     *clientStream
+	timer  *time.Timer   // if non-nil, we're doing a delayed write
+	fnonce *sync.Once    // to call fn with
+	fn     func()        // the code to run in the goroutine, writing the body
+	resc   chan error    // result of fn's execution
+	delay  time.Duration // how long we should delay a delayed write for
+}
+
+func (t *Transport) getBodyWriterState(cs *clientStream, body io.Reader) (s bodyWriterState) {
+	s.cs = cs
+	if body == nil {
+		return
+	}
+	resc := make(chan error, 1)
+	s.resc = resc
+	s.fn = func() {
+		resc <- cs.writeRequestBody(body, cs.req.Body)
+	}
+	s.delay = t.expectContinueTimeout()
+	if s.delay == 0 ||
+		!httplex.HeaderValuesContainsToken(
+			cs.req.Header["Expect"],
+			"100-continue") {
+		return
+	}
+	s.fnonce = new(sync.Once)
+
+	// Arm the timer with a very large duration, which we'll
+	// intentionally lower later. It has to be large now because
+	// we need a handle to it before writing the headers, but the
+	// s.delay value is defined to not start until after the
+	// request headers were written.
+	const hugeDuration = 365 * 24 * time.Hour
+	s.timer = time.AfterFunc(hugeDuration, func() {
+		s.fnonce.Do(s.fn)
+	})
+	return
+}
+
+func (s bodyWriterState) cancel() {
+	if s.timer != nil {
+		s.timer.Stop()
+	}
+}
+
+func (s bodyWriterState) on100() {
+	if s.timer == nil {
+		// If we didn't do a delayed write, ignore the server's
+		// bogus 100 continue response.
+		return
+	}
+	s.timer.Stop()
+	go func() { s.fnonce.Do(s.fn) }()
+}
+
+// scheduleBodyWrite starts writing the body, either immediately (in
+// the common case) or after the delay timeout. It should not be
+// called until after the headers have been written.
+func (s bodyWriterState) scheduleBodyWrite() {
+	if s.timer == nil {
+		// We're not doing a delayed write (see
+		// getBodyWriterState), so just start the writing
+		// goroutine immediately.
+		go s.fn()
+		return
+	}
+	traceWait100Continue(s.cs.trace)
+	if s.timer.Stop() {
+		s.timer.Reset(s.delay)
+	}
+}
diff --git a/vendor/golang.org/x/net/http2/write.go b/vendor/golang.org/x/net/http2/write.go
new file mode 100644
index 0000000..27ef0dd
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/write.go
@@ -0,0 +1,264 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http2
+
+import (
+	"bytes"
+	"fmt"
+	"log"
+	"net/http"
+	"time"
+
+	"golang.org/x/net/http2/hpack"
+	"golang.org/x/net/lex/httplex"
+)
+
+// writeFramer is implemented by any type that is used to write frames.
+type writeFramer interface {
+	writeFrame(writeContext) error
+}
+
+// writeContext is the interface needed by the various frame writer
+// types below. All the writeFrame methods below are scheduled via the
+// frame writing scheduler (see writeScheduler in writesched.go).
+//
+// This interface is implemented by *serverConn.
+//
+// TODO: decide whether to a) use this in the client code (which didn't
+// end up using this yet, because it has a simpler design, not
+// currently implementing priorities), or b) delete this and
+// make the server code a bit more concrete.
+type writeContext interface {
+	Framer() *Framer
+	Flush() error
+	CloseConn() error
+	// HeaderEncoder returns an HPACK encoder that writes to the
+	// returned buffer.
+	HeaderEncoder() (*hpack.Encoder, *bytes.Buffer)
+}
+
+// endsStream reports whether the given frame writer w will locally
+// close the stream.
+func endsStream(w writeFramer) bool {
+	switch v := w.(type) {
+	case *writeData:
+		return v.endStream
+	case *writeResHeaders:
+		return v.endStream
+	case nil:
+		// This can only happen if the caller reuses w after it's
+		// been intentionally nil'ed out to prevent use. Keep this
+		// here to catch future refactoring breaking it.
+		panic("endsStream called on nil writeFramer")
+	}
+	return false
+}
+
+type flushFrameWriter struct{}
+
+func (flushFrameWriter) writeFrame(ctx writeContext) error {
+	return ctx.Flush()
+}
+
+type writeSettings []Setting
+
+func (s writeSettings) writeFrame(ctx writeContext) error {
+	return ctx.Framer().WriteSettings([]Setting(s)...)
+}
+
+type writeGoAway struct {
+	maxStreamID uint32
+	code        ErrCode
+}
+
+func (p *writeGoAway) writeFrame(ctx writeContext) error {
+	err := ctx.Framer().WriteGoAway(p.maxStreamID, p.code, nil)
+	if p.code != 0 {
+		ctx.Flush() // ignore error: we're hanging up on them anyway
+		time.Sleep(50 * time.Millisecond)
+		ctx.CloseConn()
+	}
+	return err
+}
+
+type writeData struct {
+	streamID  uint32
+	p         []byte
+	endStream bool
+}
+
+func (w *writeData) String() string {
+	return fmt.Sprintf("writeData(stream=%d, p=%d, endStream=%v)", w.streamID, len(w.p), w.endStream)
+}
+
+func (w *writeData) writeFrame(ctx writeContext) error {
+	return ctx.Framer().WriteData(w.streamID, w.endStream, w.p)
+}
+
+// handlerPanicRST is the message sent from handler goroutines when
+// the handler panics.
+type handlerPanicRST struct {
+	StreamID uint32
+}
+
+func (hp handlerPanicRST) writeFrame(ctx writeContext) error {
+	return ctx.Framer().WriteRSTStream(hp.StreamID, ErrCodeInternal)
+}
+
+func (se StreamError) writeFrame(ctx writeContext) error {
+	return ctx.Framer().WriteRSTStream(se.StreamID, se.Code)
+}
+
+type writePingAck struct{ pf *PingFrame }
+
+func (w writePingAck) writeFrame(ctx writeContext) error {
+	return ctx.Framer().WritePing(true, w.pf.Data)
+}
+
+type writeSettingsAck struct{}
+
+func (writeSettingsAck) writeFrame(ctx writeContext) error {
+	return ctx.Framer().WriteSettingsAck()
+}
+
+// writeResHeaders is a request to write a HEADERS and 0+ CONTINUATION frames
+// for HTTP response headers or trailers from a server handler.
+type writeResHeaders struct {
+	streamID    uint32
+	httpResCode int         // 0 means no ":status" line
+	h           http.Header // may be nil
+	trailers    []string    // if non-nil, which keys of h to write. nil means all.
+	endStream   bool
+
+	date          string
+	contentType   string
+	contentLength string
+}
+
+func encKV(enc *hpack.Encoder, k, v string) {
+	if VerboseLogs {
+		log.Printf("http2: server encoding header %q = %q", k, v)
+	}
+	enc.WriteField(hpack.HeaderField{Name: k, Value: v})
+}
+
+func (w *writeResHeaders) writeFrame(ctx writeContext) error {
+	enc, buf := ctx.HeaderEncoder()
+	buf.Reset()
+
+	if w.httpResCode != 0 {
+		encKV(enc, ":status", httpCodeString(w.httpResCode))
+	}
+
+	encodeHeaders(enc, w.h, w.trailers)
+
+	if w.contentType != "" {
+		encKV(enc, "content-type", w.contentType)
+	}
+	if w.contentLength != "" {
+		encKV(enc, "content-length", w.contentLength)
+	}
+	if w.date != "" {
+		encKV(enc, "date", w.date)
+	}
+
+	headerBlock := buf.Bytes()
+	if len(headerBlock) == 0 && w.trailers == nil {
+		panic("unexpected empty hpack")
+	}
+
+	// For now we're lazy and just pick the minimum MAX_FRAME_SIZE
+	// that all peers must support (16KB). Later we could care
+	// more and send larger frames if the peer advertised it, but
+	// there's little point. Most headers are small anyway (so we
+	// generally won't have CONTINUATION frames), and extra frames
+	// only waste 9 bytes anyway.
+	const maxFrameSize = 16384
+
+	first := true
+	for len(headerBlock) > 0 {
+		frag := headerBlock
+		if len(frag) > maxFrameSize {
+			frag = frag[:maxFrameSize]
+		}
+		headerBlock = headerBlock[len(frag):]
+		endHeaders := len(headerBlock) == 0
+		var err error
+		if first {
+			first = false
+			err = ctx.Framer().WriteHeaders(HeadersFrameParam{
+				StreamID:      w.streamID,
+				BlockFragment: frag,
+				EndStream:     w.endStream,
+				EndHeaders:    endHeaders,
+			})
+		} else {
+			err = ctx.Framer().WriteContinuation(w.streamID, endHeaders, frag)
+		}
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+type write100ContinueHeadersFrame struct {
+	streamID uint32
+}
+
+func (w write100ContinueHeadersFrame) writeFrame(ctx writeContext) error {
+	enc, buf := ctx.HeaderEncoder()
+	buf.Reset()
+	encKV(enc, ":status", "100")
+	return ctx.Framer().WriteHeaders(HeadersFrameParam{
+		StreamID:      w.streamID,
+		BlockFragment: buf.Bytes(),
+		EndStream:     false,
+		EndHeaders:    true,
+	})
+}
+
+type writeWindowUpdate struct {
+	streamID uint32 // or 0 for conn-level
+	n        uint32
+}
+
+func (wu writeWindowUpdate) writeFrame(ctx writeContext) error {
+	return ctx.Framer().WriteWindowUpdate(wu.streamID, wu.n)
+}
+
+func encodeHeaders(enc *hpack.Encoder, h http.Header, keys []string) {
+	if keys == nil {
+		sorter := sorterPool.Get().(*sorter)
+		// Using defer here, since the returned keys from the
+		// sorter.Keys method is only valid until the sorter
+		// is returned:
+		defer sorterPool.Put(sorter)
+		keys = sorter.Keys(h)
+	}
+	for _, k := range keys {
+		vv := h[k]
+		k = lowerHeader(k)
+		if !validWireHeaderFieldName(k) {
+			// Skip it as backup paranoia. Per
+			// golang.org/issue/14048, these should
+			// already be rejected at a higher level.
+			continue
+		}
+		isTE := k == "transfer-encoding"
+		for _, v := range vv {
+			if !httplex.ValidHeaderFieldValue(v) {
+				// TODO: return an error? golang.org/issue/14048
+				// For now just omit it.
+				continue
+			}
+			// TODO: more of "8.1.2.2 Connection-Specific Header Fields"
+			if isTE && v != "trailers" {
+				continue
+			}
+			encKV(enc, k, v)
+		}
+	}
+}
diff --git a/vendor/golang.org/x/net/http2/writesched.go b/vendor/golang.org/x/net/http2/writesched.go
new file mode 100644
index 0000000..c24316c
--- /dev/null
+++ b/vendor/golang.org/x/net/http2/writesched.go
@@ -0,0 +1,283 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http2
+
+import "fmt"
+
+// frameWriteMsg is a request to write a frame.
+type frameWriteMsg struct {
+	// write is the interface value that does the writing, once the
+	// writeScheduler (below) has decided to select this frame
+	// to write. The write functions are all defined in write.go.
+	write writeFramer
+
+	stream *stream // used for prioritization. nil for non-stream frames.
+
+	// done, if non-nil, must be a buffered channel with space for
+	// 1 message and is sent the return value from write (or an
+	// earlier error) when the frame has been written.
+	done chan error
+}
+
+// for debugging only:
+func (wm frameWriteMsg) String() string {
+	var streamID uint32
+	if wm.stream != nil {
+		streamID = wm.stream.id
+	}
+	var des string
+	if s, ok := wm.write.(fmt.Stringer); ok {
+		des = s.String()
+	} else {
+		des = fmt.Sprintf("%T", wm.write)
+	}
+	return fmt.Sprintf("[frameWriteMsg stream=%d, ch=%v, type: %v]", streamID, wm.done != nil, des)
+}
+
+// writeScheduler tracks pending frames to write, priorities, and decides
+// the next one to use. It is not thread-safe.
+type writeScheduler struct {
+	// zero are frames not associated with a specific stream.
+	// They're sent before any stream-specific freams.
+	zero writeQueue
+
+	// maxFrameSize is the maximum size of a DATA frame
+	// we'll write. Must be non-zero and between 16K-16M.
+	maxFrameSize uint32
+
+	// sq contains the stream-specific queues, keyed by stream ID.
+	// when a stream is idle, it's deleted from the map.
+	sq map[uint32]*writeQueue
+
+	// canSend is a slice of memory that's reused between frame
+	// scheduling decisions to hold the list of writeQueues (from sq)
+	// which have enough flow control data to send. After canSend is
+	// built, the best is selected.
+	canSend []*writeQueue
+
+	// pool of empty queues for reuse.
+	queuePool []*writeQueue
+}
+
+func (ws *writeScheduler) putEmptyQueue(q *writeQueue) {
+	if len(q.s) != 0 {
+		panic("queue must be empty")
+	}
+	ws.queuePool = append(ws.queuePool, q)
+}
+
+func (ws *writeScheduler) getEmptyQueue() *writeQueue {
+	ln := len(ws.queuePool)
+	if ln == 0 {
+		return new(writeQueue)
+	}
+	q := ws.queuePool[ln-1]
+	ws.queuePool = ws.queuePool[:ln-1]
+	return q
+}
+
+func (ws *writeScheduler) empty() bool { return ws.zero.empty() && len(ws.sq) == 0 }
+
+func (ws *writeScheduler) add(wm frameWriteMsg) {
+	st := wm.stream
+	if st == nil {
+		ws.zero.push(wm)
+	} else {
+		ws.streamQueue(st.id).push(wm)
+	}
+}
+
+func (ws *writeScheduler) streamQueue(streamID uint32) *writeQueue {
+	if q, ok := ws.sq[streamID]; ok {
+		return q
+	}
+	if ws.sq == nil {
+		ws.sq = make(map[uint32]*writeQueue)
+	}
+	q := ws.getEmptyQueue()
+	ws.sq[streamID] = q
+	return q
+}
+
+// take returns the most important frame to write and removes it from the scheduler.
+// It is illegal to call this if the scheduler is empty or if there are no connection-level
+// flow control bytes available.
+func (ws *writeScheduler) take() (wm frameWriteMsg, ok bool) {
+	if ws.maxFrameSize == 0 {
+		panic("internal error: ws.maxFrameSize not initialized or invalid")
+	}
+
+	// If there any frames not associated with streams, prefer those first.
+	// These are usually SETTINGS, etc.
+	if !ws.zero.empty() {
+		return ws.zero.shift(), true
+	}
+	if len(ws.sq) == 0 {
+		return
+	}
+
+	// Next, prioritize frames on streams that aren't DATA frames (no cost).
+	for id, q := range ws.sq {
+		if q.firstIsNoCost() {
+			return ws.takeFrom(id, q)
+		}
+	}
+
+	// Now, all that remains are DATA frames with non-zero bytes to
+	// send. So pick the best one.
+	if len(ws.canSend) != 0 {
+		panic("should be empty")
+	}
+	for _, q := range ws.sq {
+		if n := ws.streamWritableBytes(q); n > 0 {
+			ws.canSend = append(ws.canSend, q)
+		}
+	}
+	if len(ws.canSend) == 0 {
+		return
+	}
+	defer ws.zeroCanSend()
+
+	// TODO: find the best queue
+	q := ws.canSend[0]
+
+	return ws.takeFrom(q.streamID(), q)
+}
+
+// zeroCanSend is defered from take.
+func (ws *writeScheduler) zeroCanSend() {
+	for i := range ws.canSend {
+		ws.canSend[i] = nil
+	}
+	ws.canSend = ws.canSend[:0]
+}
+
+// streamWritableBytes returns the number of DATA bytes we could write
+// from the given queue's stream, if this stream/queue were
+// selected. It is an error to call this if q's head isn't a
+// *writeData.
+func (ws *writeScheduler) streamWritableBytes(q *writeQueue) int32 {
+	wm := q.head()
+	ret := wm.stream.flow.available() // max we can write
+	if ret == 0 {
+		return 0
+	}
+	if int32(ws.maxFrameSize) < ret {
+		ret = int32(ws.maxFrameSize)
+	}
+	if ret == 0 {
+		panic("internal error: ws.maxFrameSize not initialized or invalid")
+	}
+	wd := wm.write.(*writeData)
+	if len(wd.p) < int(ret) {
+		ret = int32(len(wd.p))
+	}
+	return ret
+}
+
+func (ws *writeScheduler) takeFrom(id uint32, q *writeQueue) (wm frameWriteMsg, ok bool) {
+	wm = q.head()
+	// If the first item in this queue costs flow control tokens
+	// and we don't have enough, write as much as we can.
+	if wd, ok := wm.write.(*writeData); ok && len(wd.p) > 0 {
+		allowed := wm.stream.flow.available() // max we can write
+		if allowed == 0 {
+			// No quota available. Caller can try the next stream.
+			return frameWriteMsg{}, false
+		}
+		if int32(ws.maxFrameSize) < allowed {
+			allowed = int32(ws.maxFrameSize)
+		}
+		// TODO: further restrict the allowed size, because even if
+		// the peer says it's okay to write 16MB data frames, we might
+		// want to write smaller ones to properly weight competing
+		// streams' priorities.
+
+		if len(wd.p) > int(allowed) {
+			wm.stream.flow.take(allowed)
+			chunk := wd.p[:allowed]
+			wd.p = wd.p[allowed:]
+			// Make up a new write message of a valid size, rather
+			// than shifting one off the queue.
+			return frameWriteMsg{
+				stream: wm.stream,
+				write: &writeData{
+					streamID: wd.streamID,
+					p:        chunk,
+					// even if the original had endStream set, there
+					// arebytes remaining because len(wd.p) > allowed,
+					// so we know endStream is false:
+					endStream: false,
+				},
+				// our caller is blocking on the final DATA frame, not
+				// these intermediates, so no need to wait:
+				done: nil,
+			}, true
+		}
+		wm.stream.flow.take(int32(len(wd.p)))
+	}
+
+	q.shift()
+	if q.empty() {
+		ws.putEmptyQueue(q)
+		delete(ws.sq, id)
+	}
+	return wm, true
+}
+
+func (ws *writeScheduler) forgetStream(id uint32) {
+	q, ok := ws.sq[id]
+	if !ok {
+		return
+	}
+	delete(ws.sq, id)
+
+	// But keep it for others later.
+	for i := range q.s {
+		q.s[i] = frameWriteMsg{}
+	}
+	q.s = q.s[:0]
+	ws.putEmptyQueue(q)
+}
+
+type writeQueue struct {
+	s []frameWriteMsg
+}
+
+// streamID returns the stream ID for a non-empty stream-specific queue.
+func (q *writeQueue) streamID() uint32 { return q.s[0].stream.id }
+
+func (q *writeQueue) empty() bool { return len(q.s) == 0 }
+
+func (q *writeQueue) push(wm frameWriteMsg) {
+	q.s = append(q.s, wm)
+}
+
+// head returns the next item that would be removed by shift.
+func (q *writeQueue) head() frameWriteMsg {
+	if len(q.s) == 0 {
+		panic("invalid use of queue")
+	}
+	return q.s[0]
+}
+
+func (q *writeQueue) shift() frameWriteMsg {
+	if len(q.s) == 0 {
+		panic("invalid use of queue")
+	}
+	wm := q.s[0]
+	// TODO: less copy-happy queue.
+	copy(q.s, q.s[1:])
+	q.s[len(q.s)-1] = frameWriteMsg{}
+	q.s = q.s[:len(q.s)-1]
+	return wm
+}
+
+func (q *writeQueue) firstIsNoCost() bool {
+	if df, ok := q.s[0].write.(*writeData); ok {
+		return len(df.p) == 0
+	}
+	return true
+}
diff --git a/vendor/golang.org/x/net/internal/timeseries/timeseries.go b/vendor/golang.org/x/net/internal/timeseries/timeseries.go
new file mode 100644
index 0000000..1119f34
--- /dev/null
+++ b/vendor/golang.org/x/net/internal/timeseries/timeseries.go
@@ -0,0 +1,525 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package timeseries implements a time series structure for stats collection.
+package timeseries // import "golang.org/x/net/internal/timeseries"
+
+import (
+	"fmt"
+	"log"
+	"time"
+)
+
+const (
+	timeSeriesNumBuckets       = 64
+	minuteHourSeriesNumBuckets = 60
+)
+
+var timeSeriesResolutions = []time.Duration{
+	1 * time.Second,
+	10 * time.Second,
+	1 * time.Minute,
+	10 * time.Minute,
+	1 * time.Hour,
+	6 * time.Hour,
+	24 * time.Hour,          // 1 day
+	7 * 24 * time.Hour,      // 1 week
+	4 * 7 * 24 * time.Hour,  // 4 weeks
+	16 * 7 * 24 * time.Hour, // 16 weeks
+}
+
+var minuteHourSeriesResolutions = []time.Duration{
+	1 * time.Second,
+	1 * time.Minute,
+}
+
+// An Observable is a kind of data that can be aggregated in a time series.
+type Observable interface {
+	Multiply(ratio float64)    // Multiplies the data in self by a given ratio
+	Add(other Observable)      // Adds the data from a different observation to self
+	Clear()                    // Clears the observation so it can be reused.
+	CopyFrom(other Observable) // Copies the contents of a given observation to self
+}
+
+// Float attaches the methods of Observable to a float64.
+type Float float64
+
+// NewFloat returns a Float.
+func NewFloat() Observable {
+	f := Float(0)
+	return &f
+}
+
+// String returns the float as a string.
+func (f *Float) String() string { return fmt.Sprintf("%g", f.Value()) }
+
+// Value returns the float's value.
+func (f *Float) Value() float64 { return float64(*f) }
+
+func (f *Float) Multiply(ratio float64) { *f *= Float(ratio) }
+
+func (f *Float) Add(other Observable) {
+	o := other.(*Float)
+	*f += *o
+}
+
+func (f *Float) Clear() { *f = 0 }
+
+func (f *Float) CopyFrom(other Observable) {
+	o := other.(*Float)
+	*f = *o
+}
+
+// A Clock tells the current time.
+type Clock interface {
+	Time() time.Time
+}
+
+type defaultClock int
+
+var defaultClockInstance defaultClock
+
+func (defaultClock) Time() time.Time { return time.Now() }
+
+// Information kept per level. Each level consists of a circular list of
+// observations. The start of the level may be derived from end and the
+// len(buckets) * sizeInMillis.
+type tsLevel struct {
+	oldest   int               // index to oldest bucketed Observable
+	newest   int               // index to newest bucketed Observable
+	end      time.Time         // end timestamp for this level
+	size     time.Duration     // duration of the bucketed Observable
+	buckets  []Observable      // collections of observations
+	provider func() Observable // used for creating new Observable
+}
+
+func (l *tsLevel) Clear() {
+	l.oldest = 0
+	l.newest = len(l.buckets) - 1
+	l.end = time.Time{}
+	for i := range l.buckets {
+		if l.buckets[i] != nil {
+			l.buckets[i].Clear()
+			l.buckets[i] = nil
+		}
+	}
+}
+
+func (l *tsLevel) InitLevel(size time.Duration, numBuckets int, f func() Observable) {
+	l.size = size
+	l.provider = f
+	l.buckets = make([]Observable, numBuckets)
+}
+
+// Keeps a sequence of levels. Each level is responsible for storing data at
+// a given resolution. For example, the first level stores data at a one
+// minute resolution while the second level stores data at a one hour
+// resolution.
+
+// Each level is represented by a sequence of buckets. Each bucket spans an
+// interval equal to the resolution of the level. New observations are added
+// to the last bucket.
+type timeSeries struct {
+	provider    func() Observable // make more Observable
+	numBuckets  int               // number of buckets in each level
+	levels      []*tsLevel        // levels of bucketed Observable
+	lastAdd     time.Time         // time of last Observable tracked
+	total       Observable        // convenient aggregation of all Observable
+	clock       Clock             // Clock for getting current time
+	pending     Observable        // observations not yet bucketed
+	pendingTime time.Time         // what time are we keeping in pending
+	dirty       bool              // if there are pending observations
+}
+
+// init initializes a level according to the supplied criteria.
+func (ts *timeSeries) init(resolutions []time.Duration, f func() Observable, numBuckets int, clock Clock) {
+	ts.provider = f
+	ts.numBuckets = numBuckets
+	ts.clock = clock
+	ts.levels = make([]*tsLevel, len(resolutions))
+
+	for i := range resolutions {
+		if i > 0 && resolutions[i-1] >= resolutions[i] {
+			log.Print("timeseries: resolutions must be monotonically increasing")
+			break
+		}
+		newLevel := new(tsLevel)
+		newLevel.InitLevel(resolutions[i], ts.numBuckets, ts.provider)
+		ts.levels[i] = newLevel
+	}
+
+	ts.Clear()
+}
+
+// Clear removes all observations from the time series.
+func (ts *timeSeries) Clear() {
+	ts.lastAdd = time.Time{}
+	ts.total = ts.resetObservation(ts.total)
+	ts.pending = ts.resetObservation(ts.pending)
+	ts.pendingTime = time.Time{}
+	ts.dirty = false
+
+	for i := range ts.levels {
+		ts.levels[i].Clear()
+	}
+}
+
+// Add records an observation at the current time.
+func (ts *timeSeries) Add(observation Observable) {
+	ts.AddWithTime(observation, ts.clock.Time())
+}
+
+// AddWithTime records an observation at the specified time.
+func (ts *timeSeries) AddWithTime(observation Observable, t time.Time) {
+
+	smallBucketDuration := ts.levels[0].size
+
+	if t.After(ts.lastAdd) {
+		ts.lastAdd = t
+	}
+
+	if t.After(ts.pendingTime) {
+		ts.advance(t)
+		ts.mergePendingUpdates()
+		ts.pendingTime = ts.levels[0].end
+		ts.pending.CopyFrom(observation)
+		ts.dirty = true
+	} else if t.After(ts.pendingTime.Add(-1 * smallBucketDuration)) {
+		// The observation is close enough to go into the pending bucket.
+		// This compensates for clock skewing and small scheduling delays
+		// by letting the update stay in the fast path.
+		ts.pending.Add(observation)
+		ts.dirty = true
+	} else {
+		ts.mergeValue(observation, t)
+	}
+}
+
+// mergeValue inserts the observation at the specified time in the past into all levels.
+func (ts *timeSeries) mergeValue(observation Observable, t time.Time) {
+	for _, level := range ts.levels {
+		index := (ts.numBuckets - 1) - int(level.end.Sub(t)/level.size)
+		if 0 <= index && index < ts.numBuckets {
+			bucketNumber := (level.oldest + index) % ts.numBuckets
+			if level.buckets[bucketNumber] == nil {
+				level.buckets[bucketNumber] = level.provider()
+			}
+			level.buckets[bucketNumber].Add(observation)
+		}
+	}
+	ts.total.Add(observation)
+}
+
+// mergePendingUpdates applies the pending updates into all levels.
+func (ts *timeSeries) mergePendingUpdates() {
+	if ts.dirty {
+		ts.mergeValue(ts.pending, ts.pendingTime)
+		ts.pending = ts.resetObservation(ts.pending)
+		ts.dirty = false
+	}
+}
+
+// advance cycles the buckets at each level until the latest bucket in
+// each level can hold the time specified.
+func (ts *timeSeries) advance(t time.Time) {
+	if !t.After(ts.levels[0].end) {
+		return
+	}
+	for i := 0; i < len(ts.levels); i++ {
+		level := ts.levels[i]
+		if !level.end.Before(t) {
+			break
+		}
+
+		// If the time is sufficiently far, just clear the level and advance
+		// directly.
+		if !t.Before(level.end.Add(level.size * time.Duration(ts.numBuckets))) {
+			for _, b := range level.buckets {
+				ts.resetObservation(b)
+			}
+			level.end = time.Unix(0, (t.UnixNano()/level.size.Nanoseconds())*level.size.Nanoseconds())
+		}
+
+		for t.After(level.end) {
+			level.end = level.end.Add(level.size)
+			level.newest = level.oldest
+			level.oldest = (level.oldest + 1) % ts.numBuckets
+			ts.resetObservation(level.buckets[level.newest])
+		}
+
+		t = level.end
+	}
+}
+
+// Latest returns the sum of the num latest buckets from the level.
+func (ts *timeSeries) Latest(level, num int) Observable {
+	now := ts.clock.Time()
+	if ts.levels[0].end.Before(now) {
+		ts.advance(now)
+	}
+
+	ts.mergePendingUpdates()
+
+	result := ts.provider()
+	l := ts.levels[level]
+	index := l.newest
+
+	for i := 0; i < num; i++ {
+		if l.buckets[index] != nil {
+			result.Add(l.buckets[index])
+		}
+		if index == 0 {
+			index = ts.numBuckets
+		}
+		index--
+	}
+
+	return result
+}
+
+// LatestBuckets returns a copy of the num latest buckets from level.
+func (ts *timeSeries) LatestBuckets(level, num int) []Observable {
+	if level < 0 || level > len(ts.levels) {
+		log.Print("timeseries: bad level argument: ", level)
+		return nil
+	}
+	if num < 0 || num >= ts.numBuckets {
+		log.Print("timeseries: bad num argument: ", num)
+		return nil
+	}
+
+	results := make([]Observable, num)
+	now := ts.clock.Time()
+	if ts.levels[0].end.Before(now) {
+		ts.advance(now)
+	}
+
+	ts.mergePendingUpdates()
+
+	l := ts.levels[level]
+	index := l.newest
+
+	for i := 0; i < num; i++ {
+		result := ts.provider()
+		results[i] = result
+		if l.buckets[index] != nil {
+			result.CopyFrom(l.buckets[index])
+		}
+
+		if index == 0 {
+			index = ts.numBuckets
+		}
+		index -= 1
+	}
+	return results
+}
+
+// ScaleBy updates observations by scaling by factor.
+func (ts *timeSeries) ScaleBy(factor float64) {
+	for _, l := range ts.levels {
+		for i := 0; i < ts.numBuckets; i++ {
+			l.buckets[i].Multiply(factor)
+		}
+	}
+
+	ts.total.Multiply(factor)
+	ts.pending.Multiply(factor)
+}
+
+// Range returns the sum of observations added over the specified time range.
+// If start or finish times don't fall on bucket boundaries of the same
+// level, then return values are approximate answers.
+func (ts *timeSeries) Range(start, finish time.Time) Observable {
+	return ts.ComputeRange(start, finish, 1)[0]
+}
+
+// Recent returns the sum of observations from the last delta.
+func (ts *timeSeries) Recent(delta time.Duration) Observable {
+	now := ts.clock.Time()
+	return ts.Range(now.Add(-delta), now)
+}
+
+// Total returns the total of all observations.
+func (ts *timeSeries) Total() Observable {
+	ts.mergePendingUpdates()
+	return ts.total
+}
+
+// ComputeRange computes a specified number of values into a slice using
+// the observations recorded over the specified time period. The return
+// values are approximate if the start or finish times don't fall on the
+// bucket boundaries at the same level or if the number of buckets spanning
+// the range is not an integral multiple of num.
+func (ts *timeSeries) ComputeRange(start, finish time.Time, num int) []Observable {
+	if start.After(finish) {
+		log.Printf("timeseries: start > finish, %v>%v", start, finish)
+		return nil
+	}
+
+	if num < 0 {
+		log.Printf("timeseries: num < 0, %v", num)
+		return nil
+	}
+
+	results := make([]Observable, num)
+
+	for _, l := range ts.levels {
+		if !start.Before(l.end.Add(-l.size * time.Duration(ts.numBuckets))) {
+			ts.extract(l, start, finish, num, results)
+			return results
+		}
+	}
+
+	// Failed to find a level that covers the desired range.  So just
+	// extract from the last level, even if it doesn't cover the entire
+	// desired range.
+	ts.extract(ts.levels[len(ts.levels)-1], start, finish, num, results)
+
+	return results
+}
+
+// RecentList returns the specified number of values in slice over the most
+// recent time period of the specified range.
+func (ts *timeSeries) RecentList(delta time.Duration, num int) []Observable {
+	if delta < 0 {
+		return nil
+	}
+	now := ts.clock.Time()
+	return ts.ComputeRange(now.Add(-delta), now, num)
+}
+
+// extract returns a slice of specified number of observations from a given
+// level over a given range.
+func (ts *timeSeries) extract(l *tsLevel, start, finish time.Time, num int, results []Observable) {
+	ts.mergePendingUpdates()
+
+	srcInterval := l.size
+	dstInterval := finish.Sub(start) / time.Duration(num)
+	dstStart := start
+	srcStart := l.end.Add(-srcInterval * time.Duration(ts.numBuckets))
+
+	srcIndex := 0
+
+	// Where should scanning start?
+	if dstStart.After(srcStart) {
+		advance := dstStart.Sub(srcStart) / srcInterval
+		srcIndex += int(advance)
+		srcStart = srcStart.Add(advance * srcInterval)
+	}
+
+	// The i'th value is computed as show below.
+	// interval = (finish/start)/num
+	// i'th value = sum of observation in range
+	//   [ start + i       * interval,
+	//     start + (i + 1) * interval )
+	for i := 0; i < num; i++ {
+		results[i] = ts.resetObservation(results[i])
+		dstEnd := dstStart.Add(dstInterval)
+		for srcIndex < ts.numBuckets && srcStart.Before(dstEnd) {
+			srcEnd := srcStart.Add(srcInterval)
+			if srcEnd.After(ts.lastAdd) {
+				srcEnd = ts.lastAdd
+			}
+
+			if !srcEnd.Before(dstStart) {
+				srcValue := l.buckets[(srcIndex+l.oldest)%ts.numBuckets]
+				if !srcStart.Before(dstStart) && !srcEnd.After(dstEnd) {
+					// dst completely contains src.
+					if srcValue != nil {
+						results[i].Add(srcValue)
+					}
+				} else {
+					// dst partially overlaps src.
+					overlapStart := maxTime(srcStart, dstStart)
+					overlapEnd := minTime(srcEnd, dstEnd)
+					base := srcEnd.Sub(srcStart)
+					fraction := overlapEnd.Sub(overlapStart).Seconds() / base.Seconds()
+
+					used := ts.provider()
+					if srcValue != nil {
+						used.CopyFrom(srcValue)
+					}
+					used.Multiply(fraction)
+					results[i].Add(used)
+				}
+
+				if srcEnd.After(dstEnd) {
+					break
+				}
+			}
+			srcIndex++
+			srcStart = srcStart.Add(srcInterval)
+		}
+		dstStart = dstStart.Add(dstInterval)
+	}
+}
+
+// resetObservation clears the content so the struct may be reused.
+func (ts *timeSeries) resetObservation(observation Observable) Observable {
+	if observation == nil {
+		observation = ts.provider()
+	} else {
+		observation.Clear()
+	}
+	return observation
+}
+
+// TimeSeries tracks data at granularities from 1 second to 16 weeks.
+type TimeSeries struct {
+	timeSeries
+}
+
+// NewTimeSeries creates a new TimeSeries using the function provided for creating new Observable.
+func NewTimeSeries(f func() Observable) *TimeSeries {
+	return NewTimeSeriesWithClock(f, defaultClockInstance)
+}
+
+// NewTimeSeriesWithClock creates a new TimeSeries using the function provided for creating new Observable and the clock for
+// assigning timestamps.
+func NewTimeSeriesWithClock(f func() Observable, clock Clock) *TimeSeries {
+	ts := new(TimeSeries)
+	ts.timeSeries.init(timeSeriesResolutions, f, timeSeriesNumBuckets, clock)
+	return ts
+}
+
+// MinuteHourSeries tracks data at granularities of 1 minute and 1 hour.
+type MinuteHourSeries struct {
+	timeSeries
+}
+
+// NewMinuteHourSeries creates a new MinuteHourSeries using the function provided for creating new Observable.
+func NewMinuteHourSeries(f func() Observable) *MinuteHourSeries {
+	return NewMinuteHourSeriesWithClock(f, defaultClockInstance)
+}
+
+// NewMinuteHourSeriesWithClock creates a new MinuteHourSeries using the function provided for creating new Observable and the clock for
+// assigning timestamps.
+func NewMinuteHourSeriesWithClock(f func() Observable, clock Clock) *MinuteHourSeries {
+	ts := new(MinuteHourSeries)
+	ts.timeSeries.init(minuteHourSeriesResolutions, f,
+		minuteHourSeriesNumBuckets, clock)
+	return ts
+}
+
+func (ts *MinuteHourSeries) Minute() Observable {
+	return ts.timeSeries.Latest(0, 60)
+}
+
+func (ts *MinuteHourSeries) Hour() Observable {
+	return ts.timeSeries.Latest(1, 60)
+}
+
+func minTime(a, b time.Time) time.Time {
+	if a.Before(b) {
+		return a
+	}
+	return b
+}
+
+func maxTime(a, b time.Time) time.Time {
+	if a.After(b) {
+		return a
+	}
+	return b
+}
diff --git a/vendor/golang.org/x/net/lex/httplex/httplex.go b/vendor/golang.org/x/net/lex/httplex/httplex.go
new file mode 100644
index 0000000..bd0ec24
--- /dev/null
+++ b/vendor/golang.org/x/net/lex/httplex/httplex.go
@@ -0,0 +1,312 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package httplex contains rules around lexical matters of various
+// HTTP-related specifications.
+//
+// This package is shared by the standard library (which vendors it)
+// and x/net/http2. It comes with no API stability promise.
+package httplex
+
+import (
+	"strings"
+	"unicode/utf8"
+)
+
+var isTokenTable = [127]bool{
+	'!':  true,
+	'#':  true,
+	'$':  true,
+	'%':  true,
+	'&':  true,
+	'\'': true,
+	'*':  true,
+	'+':  true,
+	'-':  true,
+	'.':  true,
+	'0':  true,
+	'1':  true,
+	'2':  true,
+	'3':  true,
+	'4':  true,
+	'5':  true,
+	'6':  true,
+	'7':  true,
+	'8':  true,
+	'9':  true,
+	'A':  true,
+	'B':  true,
+	'C':  true,
+	'D':  true,
+	'E':  true,
+	'F':  true,
+	'G':  true,
+	'H':  true,
+	'I':  true,
+	'J':  true,
+	'K':  true,
+	'L':  true,
+	'M':  true,
+	'N':  true,
+	'O':  true,
+	'P':  true,
+	'Q':  true,
+	'R':  true,
+	'S':  true,
+	'T':  true,
+	'U':  true,
+	'W':  true,
+	'V':  true,
+	'X':  true,
+	'Y':  true,
+	'Z':  true,
+	'^':  true,
+	'_':  true,
+	'`':  true,
+	'a':  true,
+	'b':  true,
+	'c':  true,
+	'd':  true,
+	'e':  true,
+	'f':  true,
+	'g':  true,
+	'h':  true,
+	'i':  true,
+	'j':  true,
+	'k':  true,
+	'l':  true,
+	'm':  true,
+	'n':  true,
+	'o':  true,
+	'p':  true,
+	'q':  true,
+	'r':  true,
+	's':  true,
+	't':  true,
+	'u':  true,
+	'v':  true,
+	'w':  true,
+	'x':  true,
+	'y':  true,
+	'z':  true,
+	'|':  true,
+	'~':  true,
+}
+
+func IsTokenRune(r rune) bool {
+	i := int(r)
+	return i < len(isTokenTable) && isTokenTable[i]
+}
+
+func isNotToken(r rune) bool {
+	return !IsTokenRune(r)
+}
+
+// HeaderValuesContainsToken reports whether any string in values
+// contains the provided token, ASCII case-insensitively.
+func HeaderValuesContainsToken(values []string, token string) bool {
+	for _, v := range values {
+		if headerValueContainsToken(v, token) {
+			return true
+		}
+	}
+	return false
+}
+
+// isOWS reports whether b is an optional whitespace byte, as defined
+// by RFC 7230 section 3.2.3.
+func isOWS(b byte) bool { return b == ' ' || b == '\t' }
+
+// trimOWS returns x with all optional whitespace removes from the
+// beginning and end.
+func trimOWS(x string) string {
+	// TODO: consider using strings.Trim(x, " \t") instead,
+	// if and when it's fast enough. See issue 10292.
+	// But this ASCII-only code will probably always beat UTF-8
+	// aware code.
+	for len(x) > 0 && isOWS(x[0]) {
+		x = x[1:]
+	}
+	for len(x) > 0 && isOWS(x[len(x)-1]) {
+		x = x[:len(x)-1]
+	}
+	return x
+}
+
+// headerValueContainsToken reports whether v (assumed to be a
+// 0#element, in the ABNF extension described in RFC 7230 section 7)
+// contains token amongst its comma-separated tokens, ASCII
+// case-insensitively.
+func headerValueContainsToken(v string, token string) bool {
+	v = trimOWS(v)
+	if comma := strings.IndexByte(v, ','); comma != -1 {
+		return tokenEqual(trimOWS(v[:comma]), token) || headerValueContainsToken(v[comma+1:], token)
+	}
+	return tokenEqual(v, token)
+}
+
+// lowerASCII returns the ASCII lowercase version of b.
+func lowerASCII(b byte) byte {
+	if 'A' <= b && b <= 'Z' {
+		return b + ('a' - 'A')
+	}
+	return b
+}
+
+// tokenEqual reports whether t1 and t2 are equal, ASCII case-insensitively.
+func tokenEqual(t1, t2 string) bool {
+	if len(t1) != len(t2) {
+		return false
+	}
+	for i, b := range t1 {
+		if b >= utf8.RuneSelf {
+			// No UTF-8 or non-ASCII allowed in tokens.
+			return false
+		}
+		if lowerASCII(byte(b)) != lowerASCII(t2[i]) {
+			return false
+		}
+	}
+	return true
+}
+
+// isLWS reports whether b is linear white space, according
+// to http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2
+//      LWS            = [CRLF] 1*( SP | HT )
+func isLWS(b byte) bool { return b == ' ' || b == '\t' }
+
+// isCTL reports whether b is a control byte, according
+// to http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2
+//      CTL            = <any US-ASCII control character
+//                       (octets 0 - 31) and DEL (127)>
+func isCTL(b byte) bool {
+	const del = 0x7f // a CTL
+	return b < ' ' || b == del
+}
+
+// ValidHeaderFieldName reports whether v is a valid HTTP/1.x header name.
+// HTTP/2 imposes the additional restriction that uppercase ASCII
+// letters are not allowed.
+//
+//  RFC 7230 says:
+//   header-field   = field-name ":" OWS field-value OWS
+//   field-name     = token
+//   token          = 1*tchar
+//   tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." /
+//           "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA
+func ValidHeaderFieldName(v string) bool {
+	if len(v) == 0 {
+		return false
+	}
+	for _, r := range v {
+		if !IsTokenRune(r) {
+			return false
+		}
+	}
+	return true
+}
+
+// ValidHostHeader reports whether h is a valid host header.
+func ValidHostHeader(h string) bool {
+	// The latest spec is actually this:
+	//
+	// http://tools.ietf.org/html/rfc7230#section-5.4
+	//     Host = uri-host [ ":" port ]
+	//
+	// Where uri-host is:
+	//     http://tools.ietf.org/html/rfc3986#section-3.2.2
+	//
+	// But we're going to be much more lenient for now and just
+	// search for any byte that's not a valid byte in any of those
+	// expressions.
+	for i := 0; i < len(h); i++ {
+		if !validHostByte[h[i]] {
+			return false
+		}
+	}
+	return true
+}
+
+// See the validHostHeader comment.
+var validHostByte = [256]bool{
+	'0': true, '1': true, '2': true, '3': true, '4': true, '5': true, '6': true, '7': true,
+	'8': true, '9': true,
+
+	'a': true, 'b': true, 'c': true, 'd': true, 'e': true, 'f': true, 'g': true, 'h': true,
+	'i': true, 'j': true, 'k': true, 'l': true, 'm': true, 'n': true, 'o': true, 'p': true,
+	'q': true, 'r': true, 's': true, 't': true, 'u': true, 'v': true, 'w': true, 'x': true,
+	'y': true, 'z': true,
+
+	'A': true, 'B': true, 'C': true, 'D': true, 'E': true, 'F': true, 'G': true, 'H': true,
+	'I': true, 'J': true, 'K': true, 'L': true, 'M': true, 'N': true, 'O': true, 'P': true,
+	'Q': true, 'R': true, 'S': true, 'T': true, 'U': true, 'V': true, 'W': true, 'X': true,
+	'Y': true, 'Z': true,
+
+	'!':  true, // sub-delims
+	'$':  true, // sub-delims
+	'%':  true, // pct-encoded (and used in IPv6 zones)
+	'&':  true, // sub-delims
+	'(':  true, // sub-delims
+	')':  true, // sub-delims
+	'*':  true, // sub-delims
+	'+':  true, // sub-delims
+	',':  true, // sub-delims
+	'-':  true, // unreserved
+	'.':  true, // unreserved
+	':':  true, // IPv6address + Host expression's optional port
+	';':  true, // sub-delims
+	'=':  true, // sub-delims
+	'[':  true,
+	'\'': true, // sub-delims
+	']':  true,
+	'_':  true, // unreserved
+	'~':  true, // unreserved
+}
+
+// ValidHeaderFieldValue reports whether v is a valid "field-value" according to
+// http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2 :
+//
+//        message-header = field-name ":" [ field-value ]
+//        field-value    = *( field-content | LWS )
+//        field-content  = <the OCTETs making up the field-value
+//                         and consisting of either *TEXT or combinations
+//                         of token, separators, and quoted-string>
+//
+// http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2 :
+//
+//        TEXT           = <any OCTET except CTLs,
+//                          but including LWS>
+//        LWS            = [CRLF] 1*( SP | HT )
+//        CTL            = <any US-ASCII control character
+//                         (octets 0 - 31) and DEL (127)>
+//
+// RFC 7230 says:
+//  field-value    = *( field-content / obs-fold )
+//  obj-fold       =  N/A to http2, and deprecated
+//  field-content  = field-vchar [ 1*( SP / HTAB ) field-vchar ]
+//  field-vchar    = VCHAR / obs-text
+//  obs-text       = %x80-FF
+//  VCHAR          = "any visible [USASCII] character"
+//
+// http2 further says: "Similarly, HTTP/2 allows header field values
+// that are not valid. While most of the values that can be encoded
+// will not alter header field parsing, carriage return (CR, ASCII
+// 0xd), line feed (LF, ASCII 0xa), and the zero character (NUL, ASCII
+// 0x0) might be exploited by an attacker if they are translated
+// verbatim. Any request or response that contains a character not
+// permitted in a header field value MUST be treated as malformed
+// (Section 8.1.2.6). Valid characters are defined by the
+// field-content ABNF rule in Section 3.2 of [RFC7230]."
+//
+// This function does not (yet?) properly handle the rejection of
+// strings that begin or end with SP or HTAB.
+func ValidHeaderFieldValue(v string) bool {
+	for i := 0; i < len(v); i++ {
+		b := v[i]
+		if isCTL(b) && !isLWS(b) {
+			return false
+		}
+	}
+	return true
+}
diff --git a/vendor/golang.org/x/net/trace/events.go b/vendor/golang.org/x/net/trace/events.go
new file mode 100644
index 0000000..e66c7e3
--- /dev/null
+++ b/vendor/golang.org/x/net/trace/events.go
@@ -0,0 +1,524 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package trace
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"io"
+	"log"
+	"net/http"
+	"runtime"
+	"sort"
+	"strconv"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"text/tabwriter"
+	"time"
+)
+
+var eventsTmpl = template.Must(template.New("events").Funcs(template.FuncMap{
+	"elapsed":   elapsed,
+	"trimSpace": strings.TrimSpace,
+}).Parse(eventsHTML))
+
+const maxEventsPerLog = 100
+
+type bucket struct {
+	MaxErrAge time.Duration
+	String    string
+}
+
+var buckets = []bucket{
+	{0, "total"},
+	{10 * time.Second, "errs<10s"},
+	{1 * time.Minute, "errs<1m"},
+	{10 * time.Minute, "errs<10m"},
+	{1 * time.Hour, "errs<1h"},
+	{10 * time.Hour, "errs<10h"},
+	{24000 * time.Hour, "errors"},
+}
+
+// RenderEvents renders the HTML page typically served at /debug/events.
+// It does not do any auth checking; see AuthRequest for the default auth check
+// used by the handler registered on http.DefaultServeMux.
+// req may be nil.
+func RenderEvents(w http.ResponseWriter, req *http.Request, sensitive bool) {
+	now := time.Now()
+	data := &struct {
+		Families []string // family names
+		Buckets  []bucket
+		Counts   [][]int // eventLog count per family/bucket
+
+		// Set when a bucket has been selected.
+		Family    string
+		Bucket    int
+		EventLogs eventLogs
+		Expanded  bool
+	}{
+		Buckets: buckets,
+	}
+
+	data.Families = make([]string, 0, len(families))
+	famMu.RLock()
+	for name := range families {
+		data.Families = append(data.Families, name)
+	}
+	famMu.RUnlock()
+	sort.Strings(data.Families)
+
+	// Count the number of eventLogs in each family for each error age.
+	data.Counts = make([][]int, len(data.Families))
+	for i, name := range data.Families {
+		// TODO(sameer): move this loop under the family lock.
+		f := getEventFamily(name)
+		data.Counts[i] = make([]int, len(data.Buckets))
+		for j, b := range data.Buckets {
+			data.Counts[i][j] = f.Count(now, b.MaxErrAge)
+		}
+	}
+
+	if req != nil {
+		var ok bool
+		data.Family, data.Bucket, ok = parseEventsArgs(req)
+		if !ok {
+			// No-op
+		} else {
+			data.EventLogs = getEventFamily(data.Family).Copy(now, buckets[data.Bucket].MaxErrAge)
+		}
+		if data.EventLogs != nil {
+			defer data.EventLogs.Free()
+			sort.Sort(data.EventLogs)
+		}
+		if exp, err := strconv.ParseBool(req.FormValue("exp")); err == nil {
+			data.Expanded = exp
+		}
+	}
+
+	famMu.RLock()
+	defer famMu.RUnlock()
+	if err := eventsTmpl.Execute(w, data); err != nil {
+		log.Printf("net/trace: Failed executing template: %v", err)
+	}
+}
+
+func parseEventsArgs(req *http.Request) (fam string, b int, ok bool) {
+	fam, bStr := req.FormValue("fam"), req.FormValue("b")
+	if fam == "" || bStr == "" {
+		return "", 0, false
+	}
+	b, err := strconv.Atoi(bStr)
+	if err != nil || b < 0 || b >= len(buckets) {
+		return "", 0, false
+	}
+	return fam, b, true
+}
+
+// An EventLog provides a log of events associated with a specific object.
+type EventLog interface {
+	// Printf formats its arguments with fmt.Sprintf and adds the
+	// result to the event log.
+	Printf(format string, a ...interface{})
+
+	// Errorf is like Printf, but it marks this event as an error.
+	Errorf(format string, a ...interface{})
+
+	// Finish declares that this event log is complete.
+	// The event log should not be used after calling this method.
+	Finish()
+}
+
+// NewEventLog returns a new EventLog with the specified family name
+// and title.
+func NewEventLog(family, title string) EventLog {
+	el := newEventLog()
+	el.ref()
+	el.Family, el.Title = family, title
+	el.Start = time.Now()
+	el.events = make([]logEntry, 0, maxEventsPerLog)
+	el.stack = make([]uintptr, 32)
+	n := runtime.Callers(2, el.stack)
+	el.stack = el.stack[:n]
+
+	getEventFamily(family).add(el)
+	return el
+}
+
+func (el *eventLog) Finish() {
+	getEventFamily(el.Family).remove(el)
+	el.unref() // matches ref in New
+}
+
+var (
+	famMu    sync.RWMutex
+	families = make(map[string]*eventFamily) // family name => family
+)
+
+func getEventFamily(fam string) *eventFamily {
+	famMu.Lock()
+	defer famMu.Unlock()
+	f := families[fam]
+	if f == nil {
+		f = &eventFamily{}
+		families[fam] = f
+	}
+	return f
+}
+
+type eventFamily struct {
+	mu        sync.RWMutex
+	eventLogs eventLogs
+}
+
+func (f *eventFamily) add(el *eventLog) {
+	f.mu.Lock()
+	f.eventLogs = append(f.eventLogs, el)
+	f.mu.Unlock()
+}
+
+func (f *eventFamily) remove(el *eventLog) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	for i, el0 := range f.eventLogs {
+		if el == el0 {
+			copy(f.eventLogs[i:], f.eventLogs[i+1:])
+			f.eventLogs = f.eventLogs[:len(f.eventLogs)-1]
+			return
+		}
+	}
+}
+
+func (f *eventFamily) Count(now time.Time, maxErrAge time.Duration) (n int) {
+	f.mu.RLock()
+	defer f.mu.RUnlock()
+	for _, el := range f.eventLogs {
+		if el.hasRecentError(now, maxErrAge) {
+			n++
+		}
+	}
+	return
+}
+
+func (f *eventFamily) Copy(now time.Time, maxErrAge time.Duration) (els eventLogs) {
+	f.mu.RLock()
+	defer f.mu.RUnlock()
+	els = make(eventLogs, 0, len(f.eventLogs))
+	for _, el := range f.eventLogs {
+		if el.hasRecentError(now, maxErrAge) {
+			el.ref()
+			els = append(els, el)
+		}
+	}
+	return
+}
+
+type eventLogs []*eventLog
+
+// Free calls unref on each element of the list.
+func (els eventLogs) Free() {
+	for _, el := range els {
+		el.unref()
+	}
+}
+
+// eventLogs may be sorted in reverse chronological order.
+func (els eventLogs) Len() int           { return len(els) }
+func (els eventLogs) Less(i, j int) bool { return els[i].Start.After(els[j].Start) }
+func (els eventLogs) Swap(i, j int)      { els[i], els[j] = els[j], els[i] }
+
+// A logEntry is a timestamped log entry in an event log.
+type logEntry struct {
+	When    time.Time
+	Elapsed time.Duration // since previous event in log
+	NewDay  bool          // whether this event is on a different day to the previous event
+	What    string
+	IsErr   bool
+}
+
+// WhenString returns a string representation of the elapsed time of the event.
+// It will include the date if midnight was crossed.
+func (e logEntry) WhenString() string {
+	if e.NewDay {
+		return e.When.Format("2006/01/02 15:04:05.000000")
+	}
+	return e.When.Format("15:04:05.000000")
+}
+
+// An eventLog represents an active event log.
+type eventLog struct {
+	// Family is the top-level grouping of event logs to which this belongs.
+	Family string
+
+	// Title is the title of this event log.
+	Title string
+
+	// Timing information.
+	Start time.Time
+
+	// Call stack where this event log was created.
+	stack []uintptr
+
+	// Append-only sequence of events.
+	//
+	// TODO(sameer): change this to a ring buffer to avoid the array copy
+	// when we hit maxEventsPerLog.
+	mu            sync.RWMutex
+	events        []logEntry
+	LastErrorTime time.Time
+	discarded     int
+
+	refs int32 // how many buckets this is in
+}
+
+func (el *eventLog) reset() {
+	// Clear all but the mutex. Mutexes may not be copied, even when unlocked.
+	el.Family = ""
+	el.Title = ""
+	el.Start = time.Time{}
+	el.stack = nil
+	el.events = nil
+	el.LastErrorTime = time.Time{}
+	el.discarded = 0
+	el.refs = 0
+}
+
+func (el *eventLog) hasRecentError(now time.Time, maxErrAge time.Duration) bool {
+	if maxErrAge == 0 {
+		return true
+	}
+	el.mu.RLock()
+	defer el.mu.RUnlock()
+	return now.Sub(el.LastErrorTime) < maxErrAge
+}
+
+// delta returns the elapsed time since the last event or the log start,
+// and whether it spans midnight.
+// L >= el.mu
+func (el *eventLog) delta(t time.Time) (time.Duration, bool) {
+	if len(el.events) == 0 {
+		return t.Sub(el.Start), false
+	}
+	prev := el.events[len(el.events)-1].When
+	return t.Sub(prev), prev.Day() != t.Day()
+
+}
+
+func (el *eventLog) Printf(format string, a ...interface{}) {
+	el.printf(false, format, a...)
+}
+
+func (el *eventLog) Errorf(format string, a ...interface{}) {
+	el.printf(true, format, a...)
+}
+
+func (el *eventLog) printf(isErr bool, format string, a ...interface{}) {
+	e := logEntry{When: time.Now(), IsErr: isErr, What: fmt.Sprintf(format, a...)}
+	el.mu.Lock()
+	e.Elapsed, e.NewDay = el.delta(e.When)
+	if len(el.events) < maxEventsPerLog {
+		el.events = append(el.events, e)
+	} else {
+		// Discard the oldest event.
+		if el.discarded == 0 {
+			// el.discarded starts at two to count for the event it
+			// is replacing, plus the next one that we are about to
+			// drop.
+			el.discarded = 2
+		} else {
+			el.discarded++
+		}
+		// TODO(sameer): if this causes allocations on a critical path,
+		// change eventLog.What to be a fmt.Stringer, as in trace.go.
+		el.events[0].What = fmt.Sprintf("(%d events discarded)", el.discarded)
+		// The timestamp of the discarded meta-event should be
+		// the time of the last event it is representing.
+		el.events[0].When = el.events[1].When
+		copy(el.events[1:], el.events[2:])
+		el.events[maxEventsPerLog-1] = e
+	}
+	if e.IsErr {
+		el.LastErrorTime = e.When
+	}
+	el.mu.Unlock()
+}
+
+func (el *eventLog) ref() {
+	atomic.AddInt32(&el.refs, 1)
+}
+
+func (el *eventLog) unref() {
+	if atomic.AddInt32(&el.refs, -1) == 0 {
+		freeEventLog(el)
+	}
+}
+
+func (el *eventLog) When() string {
+	return el.Start.Format("2006/01/02 15:04:05.000000")
+}
+
+func (el *eventLog) ElapsedTime() string {
+	elapsed := time.Since(el.Start)
+	return fmt.Sprintf("%.6f", elapsed.Seconds())
+}
+
+func (el *eventLog) Stack() string {
+	buf := new(bytes.Buffer)
+	tw := tabwriter.NewWriter(buf, 1, 8, 1, '\t', 0)
+	printStackRecord(tw, el.stack)
+	tw.Flush()
+	return buf.String()
+}
+
+// printStackRecord prints the function + source line information
+// for a single stack trace.
+// Adapted from runtime/pprof/pprof.go.
+func printStackRecord(w io.Writer, stk []uintptr) {
+	for _, pc := range stk {
+		f := runtime.FuncForPC(pc)
+		if f == nil {
+			continue
+		}
+		file, line := f.FileLine(pc)
+		name := f.Name()
+		// Hide runtime.goexit and any runtime functions at the beginning.
+		if strings.HasPrefix(name, "runtime.") {
+			continue
+		}
+		fmt.Fprintf(w, "#   %s\t%s:%d\n", name, file, line)
+	}
+}
+
+func (el *eventLog) Events() []logEntry {
+	el.mu.RLock()
+	defer el.mu.RUnlock()
+	return el.events
+}
+
+// freeEventLogs is a freelist of *eventLog
+var freeEventLogs = make(chan *eventLog, 1000)
+
+// newEventLog returns a event log ready to use.
+func newEventLog() *eventLog {
+	select {
+	case el := <-freeEventLogs:
+		return el
+	default:
+		return new(eventLog)
+	}
+}
+
+// freeEventLog adds el to freeEventLogs if there's room.
+// This is non-blocking.
+func freeEventLog(el *eventLog) {
+	el.reset()
+	select {
+	case freeEventLogs <- el:
+	default:
+	}
+}
+
+const eventsHTML = `
+<html>
+	<head>
+		<title>events</title>
+	</head>
+	<style type="text/css">
+		body {
+			font-family: sans-serif;
+		}
+		table#req-status td.family {
+			padding-right: 2em;
+		}
+		table#req-status td.active {
+			padding-right: 1em;
+		}
+		table#req-status td.empty {
+			color: #aaa;
+		}
+		table#reqs {
+			margin-top: 1em;
+		}
+		table#reqs tr.first {
+			{{if $.Expanded}}font-weight: bold;{{end}}
+		}
+		table#reqs td {
+			font-family: monospace;
+		}
+		table#reqs td.when {
+			text-align: right;
+			white-space: nowrap;
+		}
+		table#reqs td.elapsed {
+			padding: 0 0.5em;
+			text-align: right;
+			white-space: pre;
+			width: 10em;
+		}
+		address {
+			font-size: smaller;
+			margin-top: 5em;
+		}
+	</style>
+	<body>
+
+<h1>/debug/events</h1>
+
+<table id="req-status">
+	{{range $i, $fam := .Families}}
+	<tr>
+		<td class="family">{{$fam}}</td>
+
+	        {{range $j, $bucket := $.Buckets}}
+	        {{$n := index $.Counts $i $j}}
+		<td class="{{if not $bucket.MaxErrAge}}active{{end}}{{if not $n}}empty{{end}}">
+	                {{if $n}}<a href="?fam={{$fam}}&b={{$j}}{{if $.Expanded}}&exp=1{{end}}">{{end}}
+		        [{{$n}} {{$bucket.String}}]
+			{{if $n}}</a>{{end}}
+		</td>
+                {{end}}
+
+	</tr>{{end}}
+</table>
+
+{{if $.EventLogs}}
+<hr />
+<h3>Family: {{$.Family}}</h3>
+
+{{if $.Expanded}}<a href="?fam={{$.Family}}&b={{$.Bucket}}">{{end}}
+[Summary]{{if $.Expanded}}</a>{{end}}
+
+{{if not $.Expanded}}<a href="?fam={{$.Family}}&b={{$.Bucket}}&exp=1">{{end}}
+[Expanded]{{if not $.Expanded}}</a>{{end}}
+
+<table id="reqs">
+	<tr><th>When</th><th>Elapsed</th></tr>
+	{{range $el := $.EventLogs}}
+	<tr class="first">
+		<td class="when">{{$el.When}}</td>
+		<td class="elapsed">{{$el.ElapsedTime}}</td>
+		<td>{{$el.Title}}
+	</tr>
+	{{if $.Expanded}}
+	<tr>
+		<td class="when"></td>
+		<td class="elapsed"></td>
+		<td><pre>{{$el.Stack|trimSpace}}</pre></td>
+	</tr>
+	{{range $el.Events}}
+	<tr>
+		<td class="when">{{.WhenString}}</td>
+		<td class="elapsed">{{elapsed .Elapsed}}</td>
+		<td>.{{if .IsErr}}E{{else}}.{{end}}. {{.What}}</td>
+	</tr>
+	{{end}}
+	{{end}}
+	{{end}}
+</table>
+{{end}}
+	</body>
+</html>
+`
diff --git a/vendor/golang.org/x/net/trace/histogram.go b/vendor/golang.org/x/net/trace/histogram.go
new file mode 100644
index 0000000..bb42aa5
--- /dev/null
+++ b/vendor/golang.org/x/net/trace/histogram.go
@@ -0,0 +1,356 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package trace
+
+// This file implements histogramming for RPC statistics collection.
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"log"
+	"math"
+
+	"golang.org/x/net/internal/timeseries"
+)
+
+const (
+	bucketCount = 38
+)
+
+// histogram keeps counts of values in buckets that are spaced
+// out in powers of 2: 0-1, 2-3, 4-7...
+// histogram implements timeseries.Observable
+type histogram struct {
+	sum          int64   // running total of measurements
+	sumOfSquares float64 // square of running total
+	buckets      []int64 // bucketed values for histogram
+	value        int     // holds a single value as an optimization
+	valueCount   int64   // number of values recorded for single value
+}
+
+// AddMeasurement records a value measurement observation to the histogram.
+func (h *histogram) addMeasurement(value int64) {
+	// TODO: assert invariant
+	h.sum += value
+	h.sumOfSquares += float64(value) * float64(value)
+
+	bucketIndex := getBucket(value)
+
+	if h.valueCount == 0 || (h.valueCount > 0 && h.value == bucketIndex) {
+		h.value = bucketIndex
+		h.valueCount++
+	} else {
+		h.allocateBuckets()
+		h.buckets[bucketIndex]++
+	}
+}
+
+func (h *histogram) allocateBuckets() {
+	if h.buckets == nil {
+		h.buckets = make([]int64, bucketCount)
+		h.buckets[h.value] = h.valueCount
+		h.value = 0
+		h.valueCount = -1
+	}
+}
+
+func log2(i int64) int {
+	n := 0
+	for ; i >= 0x100; i >>= 8 {
+		n += 8
+	}
+	for ; i > 0; i >>= 1 {
+		n += 1
+	}
+	return n
+}
+
+func getBucket(i int64) (index int) {
+	index = log2(i) - 1
+	if index < 0 {
+		index = 0
+	}
+	if index >= bucketCount {
+		index = bucketCount - 1
+	}
+	return
+}
+
+// Total returns the number of recorded observations.
+func (h *histogram) total() (total int64) {
+	if h.valueCount >= 0 {
+		total = h.valueCount
+	}
+	for _, val := range h.buckets {
+		total += int64(val)
+	}
+	return
+}
+
+// Average returns the average value of recorded observations.
+func (h *histogram) average() float64 {
+	t := h.total()
+	if t == 0 {
+		return 0
+	}
+	return float64(h.sum) / float64(t)
+}
+
+// Variance returns the variance of recorded observations.
+func (h *histogram) variance() float64 {
+	t := float64(h.total())
+	if t == 0 {
+		return 0
+	}
+	s := float64(h.sum) / t
+	return h.sumOfSquares/t - s*s
+}
+
+// StandardDeviation returns the standard deviation of recorded observations.
+func (h *histogram) standardDeviation() float64 {
+	return math.Sqrt(h.variance())
+}
+
+// PercentileBoundary estimates the value that the given fraction of recorded
+// observations are less than.
+func (h *histogram) percentileBoundary(percentile float64) int64 {
+	total := h.total()
+
+	// Corner cases (make sure result is strictly less than Total())
+	if total == 0 {
+		return 0
+	} else if total == 1 {
+		return int64(h.average())
+	}
+
+	percentOfTotal := round(float64(total) * percentile)
+	var runningTotal int64
+
+	for i := range h.buckets {
+		value := h.buckets[i]
+		runningTotal += value
+		if runningTotal == percentOfTotal {
+			// We hit an exact bucket boundary. If the next bucket has data, it is a
+			// good estimate of the value. If the bucket is empty, we interpolate the
+			// midpoint between the next bucket's boundary and the next non-zero
+			// bucket. If the remaining buckets are all empty, then we use the
+			// boundary for the next bucket as the estimate.
+			j := uint8(i + 1)
+			min := bucketBoundary(j)
+			if runningTotal < total {
+				for h.buckets[j] == 0 {
+					j++
+				}
+			}
+			max := bucketBoundary(j)
+			return min + round(float64(max-min)/2)
+		} else if runningTotal > percentOfTotal {
+			// The value is in this bucket. Interpolate the value.
+			delta := runningTotal - percentOfTotal
+			percentBucket := float64(value-delta) / float64(value)
+			bucketMin := bucketBoundary(uint8(i))
+			nextBucketMin := bucketBoundary(uint8(i + 1))
+			bucketSize := nextBucketMin - bucketMin
+			return bucketMin + round(percentBucket*float64(bucketSize))
+		}
+	}
+	return bucketBoundary(bucketCount - 1)
+}
+
+// Median returns the estimated median of the observed values.
+func (h *histogram) median() int64 {
+	return h.percentileBoundary(0.5)
+}
+
+// Add adds other to h.
+func (h *histogram) Add(other timeseries.Observable) {
+	o := other.(*histogram)
+	if o.valueCount == 0 {
+		// Other histogram is empty
+	} else if h.valueCount >= 0 && o.valueCount > 0 && h.value == o.value {
+		// Both have a single bucketed value, aggregate them
+		h.valueCount += o.valueCount
+	} else {
+		// Two different values necessitate buckets in this histogram
+		h.allocateBuckets()
+		if o.valueCount >= 0 {
+			h.buckets[o.value] += o.valueCount
+		} else {
+			for i := range h.buckets {
+				h.buckets[i] += o.buckets[i]
+			}
+		}
+	}
+	h.sumOfSquares += o.sumOfSquares
+	h.sum += o.sum
+}
+
+// Clear resets the histogram to an empty state, removing all observed values.
+func (h *histogram) Clear() {
+	h.buckets = nil
+	h.value = 0
+	h.valueCount = 0
+	h.sum = 0
+	h.sumOfSquares = 0
+}
+
+// CopyFrom copies from other, which must be a *histogram, into h.
+func (h *histogram) CopyFrom(other timeseries.Observable) {
+	o := other.(*histogram)
+	if o.valueCount == -1 {
+		h.allocateBuckets()
+		copy(h.buckets, o.buckets)
+	}
+	h.sum = o.sum
+	h.sumOfSquares = o.sumOfSquares
+	h.value = o.value
+	h.valueCount = o.valueCount
+}
+
+// Multiply scales the histogram by the specified ratio.
+func (h *histogram) Multiply(ratio float64) {
+	if h.valueCount == -1 {
+		for i := range h.buckets {
+			h.buckets[i] = int64(float64(h.buckets[i]) * ratio)
+		}
+	} else {
+		h.valueCount = int64(float64(h.valueCount) * ratio)
+	}
+	h.sum = int64(float64(h.sum) * ratio)
+	h.sumOfSquares = h.sumOfSquares * ratio
+}
+
+// New creates a new histogram.
+func (h *histogram) New() timeseries.Observable {
+	r := new(histogram)
+	r.Clear()
+	return r
+}
+
+func (h *histogram) String() string {
+	return fmt.Sprintf("%d, %f, %d, %d, %v",
+		h.sum, h.sumOfSquares, h.value, h.valueCount, h.buckets)
+}
+
+// round returns the closest int64 to the argument
+func round(in float64) int64 {
+	return int64(math.Floor(in + 0.5))
+}
+
+// bucketBoundary returns the first value in the bucket.
+func bucketBoundary(bucket uint8) int64 {
+	if bucket == 0 {
+		return 0
+	}
+	return 1 << bucket
+}
+
+// bucketData holds data about a specific bucket for use in distTmpl.
+type bucketData struct {
+	Lower, Upper       int64
+	N                  int64
+	Pct, CumulativePct float64
+	GraphWidth         int
+}
+
+// data holds data about a Distribution for use in distTmpl.
+type data struct {
+	Buckets                 []*bucketData
+	Count, Median           int64
+	Mean, StandardDeviation float64
+}
+
+// maxHTMLBarWidth is the maximum width of the HTML bar for visualizing buckets.
+const maxHTMLBarWidth = 350.0
+
+// newData returns data representing h for use in distTmpl.
+func (h *histogram) newData() *data {
+	// Force the allocation of buckets to simplify the rendering implementation
+	h.allocateBuckets()
+	// We scale the bars on the right so that the largest bar is
+	// maxHTMLBarWidth pixels in width.
+	maxBucket := int64(0)
+	for _, n := range h.buckets {
+		if n > maxBucket {
+			maxBucket = n
+		}
+	}
+	total := h.total()
+	barsizeMult := maxHTMLBarWidth / float64(maxBucket)
+	var pctMult float64
+	if total == 0 {
+		pctMult = 1.0
+	} else {
+		pctMult = 100.0 / float64(total)
+	}
+
+	buckets := make([]*bucketData, len(h.buckets))
+	runningTotal := int64(0)
+	for i, n := range h.buckets {
+		if n == 0 {
+			continue
+		}
+		runningTotal += n
+		var upperBound int64
+		if i < bucketCount-1 {
+			upperBound = bucketBoundary(uint8(i + 1))
+		} else {
+			upperBound = math.MaxInt64
+		}
+		buckets[i] = &bucketData{
+			Lower:         bucketBoundary(uint8(i)),
+			Upper:         upperBound,
+			N:             n,
+			Pct:           float64(n) * pctMult,
+			CumulativePct: float64(runningTotal) * pctMult,
+			GraphWidth:    int(float64(n) * barsizeMult),
+		}
+	}
+	return &data{
+		Buckets:           buckets,
+		Count:             total,
+		Median:            h.median(),
+		Mean:              h.average(),
+		StandardDeviation: h.standardDeviation(),
+	}
+}
+
+func (h *histogram) html() template.HTML {
+	buf := new(bytes.Buffer)
+	if err := distTmpl.Execute(buf, h.newData()); err != nil {
+		buf.Reset()
+		log.Printf("net/trace: couldn't execute template: %v", err)
+	}
+	return template.HTML(buf.String())
+}
+
+// Input: data
+var distTmpl = template.Must(template.New("distTmpl").Parse(`
+<table>
+<tr>
+    <td style="padding:0.25em">Count: {{.Count}}</td>
+    <td style="padding:0.25em">Mean: {{printf "%.0f" .Mean}}</td>
+    <td style="padding:0.25em">StdDev: {{printf "%.0f" .StandardDeviation}}</td>
+    <td style="padding:0.25em">Median: {{.Median}}</td>
+</tr>
+</table>
+<hr>
+<table>
+{{range $b := .Buckets}}
+{{if $b}}
+  <tr>
+    <td style="padding:0 0 0 0.25em">[</td>
+    <td style="text-align:right;padding:0 0.25em">{{.Lower}},</td>
+    <td style="text-align:right;padding:0 0.25em">{{.Upper}})</td>
+    <td style="text-align:right;padding:0 0.25em">{{.N}}</td>
+    <td style="text-align:right;padding:0 0.25em">{{printf "%#.3f" .Pct}}%</td>
+    <td style="text-align:right;padding:0 0.25em">{{printf "%#.3f" .CumulativePct}}%</td>
+    <td><div style="background-color: blue; height: 1em; width: {{.GraphWidth}};"></div></td>
+  </tr>
+{{end}}
+{{end}}
+</table>
+`))
diff --git a/vendor/golang.org/x/net/trace/trace.go b/vendor/golang.org/x/net/trace/trace.go
new file mode 100644
index 0000000..d860fcc
--- /dev/null
+++ b/vendor/golang.org/x/net/trace/trace.go
@@ -0,0 +1,1063 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package trace implements tracing of requests and long-lived objects.
+It exports HTTP interfaces on /debug/requests and /debug/events.
+
+A trace.Trace provides tracing for short-lived objects, usually requests.
+A request handler might be implemented like this:
+
+	func fooHandler(w http.ResponseWriter, req *http.Request) {
+		tr := trace.New("mypkg.Foo", req.URL.Path)
+		defer tr.Finish()
+		...
+		tr.LazyPrintf("some event %q happened", str)
+		...
+		if err := somethingImportant(); err != nil {
+			tr.LazyPrintf("somethingImportant failed: %v", err)
+			tr.SetError()
+		}
+	}
+
+The /debug/requests HTTP endpoint organizes the traces by family,
+errors, and duration.  It also provides histogram of request duration
+for each family.
+
+A trace.EventLog provides tracing for long-lived objects, such as RPC
+connections.
+
+	// A Fetcher fetches URL paths for a single domain.
+	type Fetcher struct {
+		domain string
+		events trace.EventLog
+	}
+
+	func NewFetcher(domain string) *Fetcher {
+		return &Fetcher{
+			domain,
+			trace.NewEventLog("mypkg.Fetcher", domain),
+		}
+	}
+
+	func (f *Fetcher) Fetch(path string) (string, error) {
+		resp, err := http.Get("http://" + f.domain + "/" + path)
+		if err != nil {
+			f.events.Errorf("Get(%q) = %v", path, err)
+			return "", err
+		}
+		f.events.Printf("Get(%q) = %s", path, resp.Status)
+		...
+	}
+
+	func (f *Fetcher) Close() error {
+		f.events.Finish()
+		return nil
+	}
+
+The /debug/events HTTP endpoint organizes the event logs by family and
+by time since the last error.  The expanded view displays recent log
+entries and the log's call stack.
+*/
+package trace // import "golang.org/x/net/trace"
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"runtime"
+	"sort"
+	"strconv"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"golang.org/x/net/context"
+	"golang.org/x/net/internal/timeseries"
+)
+
+// DebugUseAfterFinish controls whether to debug uses of Trace values after finishing.
+// FOR DEBUGGING ONLY. This will slow down the program.
+var DebugUseAfterFinish = false
+
+// AuthRequest determines whether a specific request is permitted to load the
+// /debug/requests or /debug/events pages.
+//
+// It returns two bools; the first indicates whether the page may be viewed at all,
+// and the second indicates whether sensitive events will be shown.
+//
+// AuthRequest may be replaced by a program to customise its authorisation requirements.
+//
+// The default AuthRequest function returns (true, true) if and only if the request
+// comes from localhost/127.0.0.1/[::1].
+var AuthRequest = func(req *http.Request) (any, sensitive bool) {
+	// RemoteAddr is commonly in the form "IP" or "IP:port".
+	// If it is in the form "IP:port", split off the port.
+	host, _, err := net.SplitHostPort(req.RemoteAddr)
+	if err != nil {
+		host = req.RemoteAddr
+	}
+	switch host {
+	case "localhost", "127.0.0.1", "::1":
+		return true, true
+	default:
+		return false, false
+	}
+}
+
+func init() {
+	http.HandleFunc("/debug/requests", func(w http.ResponseWriter, req *http.Request) {
+		any, sensitive := AuthRequest(req)
+		if !any {
+			http.Error(w, "not allowed", http.StatusUnauthorized)
+			return
+		}
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		Render(w, req, sensitive)
+	})
+	http.HandleFunc("/debug/events", func(w http.ResponseWriter, req *http.Request) {
+		any, sensitive := AuthRequest(req)
+		if !any {
+			http.Error(w, "not allowed", http.StatusUnauthorized)
+			return
+		}
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		RenderEvents(w, req, sensitive)
+	})
+}
+
+// Render renders the HTML page typically served at /debug/requests.
+// It does not do any auth checking; see AuthRequest for the default auth check
+// used by the handler registered on http.DefaultServeMux.
+// req may be nil.
+func Render(w io.Writer, req *http.Request, sensitive bool) {
+	data := &struct {
+		Families         []string
+		ActiveTraceCount map[string]int
+		CompletedTraces  map[string]*family
+
+		// Set when a bucket has been selected.
+		Traces        traceList
+		Family        string
+		Bucket        int
+		Expanded      bool
+		Traced        bool
+		Active        bool
+		ShowSensitive bool // whether to show sensitive events
+
+		Histogram       template.HTML
+		HistogramWindow string // e.g. "last minute", "last hour", "all time"
+
+		// If non-zero, the set of traces is a partial set,
+		// and this is the total number.
+		Total int
+	}{
+		CompletedTraces: completedTraces,
+	}
+
+	data.ShowSensitive = sensitive
+	if req != nil {
+		// Allow show_sensitive=0 to force hiding of sensitive data for testing.
+		// This only goes one way; you can't use show_sensitive=1 to see things.
+		if req.FormValue("show_sensitive") == "0" {
+			data.ShowSensitive = false
+		}
+
+		if exp, err := strconv.ParseBool(req.FormValue("exp")); err == nil {
+			data.Expanded = exp
+		}
+		if exp, err := strconv.ParseBool(req.FormValue("rtraced")); err == nil {
+			data.Traced = exp
+		}
+	}
+
+	completedMu.RLock()
+	data.Families = make([]string, 0, len(completedTraces))
+	for fam := range completedTraces {
+		data.Families = append(data.Families, fam)
+	}
+	completedMu.RUnlock()
+	sort.Strings(data.Families)
+
+	// We are careful here to minimize the time spent locking activeMu,
+	// since that lock is required every time an RPC starts and finishes.
+	data.ActiveTraceCount = make(map[string]int, len(data.Families))
+	activeMu.RLock()
+	for fam, s := range activeTraces {
+		data.ActiveTraceCount[fam] = s.Len()
+	}
+	activeMu.RUnlock()
+
+	var ok bool
+	data.Family, data.Bucket, ok = parseArgs(req)
+	switch {
+	case !ok:
+		// No-op
+	case data.Bucket == -1:
+		data.Active = true
+		n := data.ActiveTraceCount[data.Family]
+		data.Traces = getActiveTraces(data.Family)
+		if len(data.Traces) < n {
+			data.Total = n
+		}
+	case data.Bucket < bucketsPerFamily:
+		if b := lookupBucket(data.Family, data.Bucket); b != nil {
+			data.Traces = b.Copy(data.Traced)
+		}
+	default:
+		if f := getFamily(data.Family, false); f != nil {
+			var obs timeseries.Observable
+			f.LatencyMu.RLock()
+			switch o := data.Bucket - bucketsPerFamily; o {
+			case 0:
+				obs = f.Latency.Minute()
+				data.HistogramWindow = "last minute"
+			case 1:
+				obs = f.Latency.Hour()
+				data.HistogramWindow = "last hour"
+			case 2:
+				obs = f.Latency.Total()
+				data.HistogramWindow = "all time"
+			}
+			f.LatencyMu.RUnlock()
+			if obs != nil {
+				data.Histogram = obs.(*histogram).html()
+			}
+		}
+	}
+
+	if data.Traces != nil {
+		defer data.Traces.Free()
+		sort.Sort(data.Traces)
+	}
+
+	completedMu.RLock()
+	defer completedMu.RUnlock()
+	if err := pageTmpl.ExecuteTemplate(w, "Page", data); err != nil {
+		log.Printf("net/trace: Failed executing template: %v", err)
+	}
+}
+
+func parseArgs(req *http.Request) (fam string, b int, ok bool) {
+	if req == nil {
+		return "", 0, false
+	}
+	fam, bStr := req.FormValue("fam"), req.FormValue("b")
+	if fam == "" || bStr == "" {
+		return "", 0, false
+	}
+	b, err := strconv.Atoi(bStr)
+	if err != nil || b < -1 {
+		return "", 0, false
+	}
+
+	return fam, b, true
+}
+
+func lookupBucket(fam string, b int) *traceBucket {
+	f := getFamily(fam, false)
+	if f == nil || b < 0 || b >= len(f.Buckets) {
+		return nil
+	}
+	return f.Buckets[b]
+}
+
+type contextKeyT string
+
+var contextKey = contextKeyT("golang.org/x/net/trace.Trace")
+
+// NewContext returns a copy of the parent context
+// and associates it with a Trace.
+func NewContext(ctx context.Context, tr Trace) context.Context {
+	return context.WithValue(ctx, contextKey, tr)
+}
+
+// FromContext returns the Trace bound to the context, if any.
+func FromContext(ctx context.Context) (tr Trace, ok bool) {
+	tr, ok = ctx.Value(contextKey).(Trace)
+	return
+}
+
+// Trace represents an active request.
+type Trace interface {
+	// LazyLog adds x to the event log. It will be evaluated each time the
+	// /debug/requests page is rendered. Any memory referenced by x will be
+	// pinned until the trace is finished and later discarded.
+	LazyLog(x fmt.Stringer, sensitive bool)
+
+	// LazyPrintf evaluates its arguments with fmt.Sprintf each time the
+	// /debug/requests page is rendered. Any memory referenced by a will be
+	// pinned until the trace is finished and later discarded.
+	LazyPrintf(format string, a ...interface{})
+
+	// SetError declares that this trace resulted in an error.
+	SetError()
+
+	// SetRecycler sets a recycler for the trace.
+	// f will be called for each event passed to LazyLog at a time when
+	// it is no longer required, whether while the trace is still active
+	// and the event is discarded, or when a completed trace is discarded.
+	SetRecycler(f func(interface{}))
+
+	// SetTraceInfo sets the trace info for the trace.
+	// This is currently unused.
+	SetTraceInfo(traceID, spanID uint64)
+
+	// SetMaxEvents sets the maximum number of events that will be stored
+	// in the trace. This has no effect if any events have already been
+	// added to the trace.
+	SetMaxEvents(m int)
+
+	// Finish declares that this trace is complete.
+	// The trace should not be used after calling this method.
+	Finish()
+}
+
+type lazySprintf struct {
+	format string
+	a      []interface{}
+}
+
+func (l *lazySprintf) String() string {
+	return fmt.Sprintf(l.format, l.a...)
+}
+
+// New returns a new Trace with the specified family and title.
+func New(family, title string) Trace {
+	tr := newTrace()
+	tr.ref()
+	tr.Family, tr.Title = family, title
+	tr.Start = time.Now()
+	tr.events = make([]event, 0, maxEventsPerTrace)
+
+	activeMu.RLock()
+	s := activeTraces[tr.Family]
+	activeMu.RUnlock()
+	if s == nil {
+		activeMu.Lock()
+		s = activeTraces[tr.Family] // check again
+		if s == nil {
+			s = new(traceSet)
+			activeTraces[tr.Family] = s
+		}
+		activeMu.Unlock()
+	}
+	s.Add(tr)
+
+	// Trigger allocation of the completed trace structure for this family.
+	// This will cause the family to be present in the request page during
+	// the first trace of this family. We don't care about the return value,
+	// nor is there any need for this to run inline, so we execute it in its
+	// own goroutine, but only if the family isn't allocated yet.
+	completedMu.RLock()
+	if _, ok := completedTraces[tr.Family]; !ok {
+		go allocFamily(tr.Family)
+	}
+	completedMu.RUnlock()
+
+	return tr
+}
+
+func (tr *trace) Finish() {
+	tr.Elapsed = time.Now().Sub(tr.Start)
+	if DebugUseAfterFinish {
+		buf := make([]byte, 4<<10) // 4 KB should be enough
+		n := runtime.Stack(buf, false)
+		tr.finishStack = buf[:n]
+	}
+
+	activeMu.RLock()
+	m := activeTraces[tr.Family]
+	activeMu.RUnlock()
+	m.Remove(tr)
+
+	f := getFamily(tr.Family, true)
+	for _, b := range f.Buckets {
+		if b.Cond.match(tr) {
+			b.Add(tr)
+		}
+	}
+	// Add a sample of elapsed time as microseconds to the family's timeseries
+	h := new(histogram)
+	h.addMeasurement(tr.Elapsed.Nanoseconds() / 1e3)
+	f.LatencyMu.Lock()
+	f.Latency.Add(h)
+	f.LatencyMu.Unlock()
+
+	tr.unref() // matches ref in New
+}
+
+const (
+	bucketsPerFamily    = 9
+	tracesPerBucket     = 10
+	maxActiveTraces     = 20 // Maximum number of active traces to show.
+	maxEventsPerTrace   = 10
+	numHistogramBuckets = 38
+)
+
+var (
+	// The active traces.
+	activeMu     sync.RWMutex
+	activeTraces = make(map[string]*traceSet) // family -> traces
+
+	// Families of completed traces.
+	completedMu     sync.RWMutex
+	completedTraces = make(map[string]*family) // family -> traces
+)
+
+type traceSet struct {
+	mu sync.RWMutex
+	m  map[*trace]bool
+
+	// We could avoid the entire map scan in FirstN by having a slice of all the traces
+	// ordered by start time, and an index into that from the trace struct, with a periodic
+	// repack of the slice after enough traces finish; we could also use a skip list or similar.
+	// However, that would shift some of the expense from /debug/requests time to RPC time,
+	// which is probably the wrong trade-off.
+}
+
+func (ts *traceSet) Len() int {
+	ts.mu.RLock()
+	defer ts.mu.RUnlock()
+	return len(ts.m)
+}
+
+func (ts *traceSet) Add(tr *trace) {
+	ts.mu.Lock()
+	if ts.m == nil {
+		ts.m = make(map[*trace]bool)
+	}
+	ts.m[tr] = true
+	ts.mu.Unlock()
+}
+
+func (ts *traceSet) Remove(tr *trace) {
+	ts.mu.Lock()
+	delete(ts.m, tr)
+	ts.mu.Unlock()
+}
+
+// FirstN returns the first n traces ordered by time.
+func (ts *traceSet) FirstN(n int) traceList {
+	ts.mu.RLock()
+	defer ts.mu.RUnlock()
+
+	if n > len(ts.m) {
+		n = len(ts.m)
+	}
+	trl := make(traceList, 0, n)
+
+	// Fast path for when no selectivity is needed.
+	if n == len(ts.m) {
+		for tr := range ts.m {
+			tr.ref()
+			trl = append(trl, tr)
+		}
+		sort.Sort(trl)
+		return trl
+	}
+
+	// Pick the oldest n traces.
+	// This is inefficient. See the comment in the traceSet struct.
+	for tr := range ts.m {
+		// Put the first n traces into trl in the order they occur.
+		// When we have n, sort trl, and thereafter maintain its order.
+		if len(trl) < n {
+			tr.ref()
+			trl = append(trl, tr)
+			if len(trl) == n {
+				// This is guaranteed to happen exactly once during this loop.
+				sort.Sort(trl)
+			}
+			continue
+		}
+		if tr.Start.After(trl[n-1].Start) {
+			continue
+		}
+
+		// Find where to insert this one.
+		tr.ref()
+		i := sort.Search(n, func(i int) bool { return trl[i].Start.After(tr.Start) })
+		trl[n-1].unref()
+		copy(trl[i+1:], trl[i:])
+		trl[i] = tr
+	}
+
+	return trl
+}
+
+func getActiveTraces(fam string) traceList {
+	activeMu.RLock()
+	s := activeTraces[fam]
+	activeMu.RUnlock()
+	if s == nil {
+		return nil
+	}
+	return s.FirstN(maxActiveTraces)
+}
+
+func getFamily(fam string, allocNew bool) *family {
+	completedMu.RLock()
+	f := completedTraces[fam]
+	completedMu.RUnlock()
+	if f == nil && allocNew {
+		f = allocFamily(fam)
+	}
+	return f
+}
+
+func allocFamily(fam string) *family {
+	completedMu.Lock()
+	defer completedMu.Unlock()
+	f := completedTraces[fam]
+	if f == nil {
+		f = newFamily()
+		completedTraces[fam] = f
+	}
+	return f
+}
+
+// family represents a set of trace buckets and associated latency information.
+type family struct {
+	// traces may occur in multiple buckets.
+	Buckets [bucketsPerFamily]*traceBucket
+
+	// latency time series
+	LatencyMu sync.RWMutex
+	Latency   *timeseries.MinuteHourSeries
+}
+
+func newFamily() *family {
+	return &family{
+		Buckets: [bucketsPerFamily]*traceBucket{
+			{Cond: minCond(0)},
+			{Cond: minCond(50 * time.Millisecond)},
+			{Cond: minCond(100 * time.Millisecond)},
+			{Cond: minCond(200 * time.Millisecond)},
+			{Cond: minCond(500 * time.Millisecond)},
+			{Cond: minCond(1 * time.Second)},
+			{Cond: minCond(10 * time.Second)},
+			{Cond: minCond(100 * time.Second)},
+			{Cond: errorCond{}},
+		},
+		Latency: timeseries.NewMinuteHourSeries(func() timeseries.Observable { return new(histogram) }),
+	}
+}
+
+// traceBucket represents a size-capped bucket of historic traces,
+// along with a condition for a trace to belong to the bucket.
+type traceBucket struct {
+	Cond cond
+
+	// Ring buffer implementation of a fixed-size FIFO queue.
+	mu     sync.RWMutex
+	buf    [tracesPerBucket]*trace
+	start  int // < tracesPerBucket
+	length int // <= tracesPerBucket
+}
+
+func (b *traceBucket) Add(tr *trace) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	i := b.start + b.length
+	if i >= tracesPerBucket {
+		i -= tracesPerBucket
+	}
+	if b.length == tracesPerBucket {
+		// "Remove" an element from the bucket.
+		b.buf[i].unref()
+		b.start++
+		if b.start == tracesPerBucket {
+			b.start = 0
+		}
+	}
+	b.buf[i] = tr
+	if b.length < tracesPerBucket {
+		b.length++
+	}
+	tr.ref()
+}
+
+// Copy returns a copy of the traces in the bucket.
+// If tracedOnly is true, only the traces with trace information will be returned.
+// The logs will be ref'd before returning; the caller should call
+// the Free method when it is done with them.
+// TODO(dsymonds): keep track of traced requests in separate buckets.
+func (b *traceBucket) Copy(tracedOnly bool) traceList {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+
+	trl := make(traceList, 0, b.length)
+	for i, x := 0, b.start; i < b.length; i++ {
+		tr := b.buf[x]
+		if !tracedOnly || tr.spanID != 0 {
+			tr.ref()
+			trl = append(trl, tr)
+		}
+		x++
+		if x == b.length {
+			x = 0
+		}
+	}
+	return trl
+}
+
+func (b *traceBucket) Empty() bool {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return b.length == 0
+}
+
+// cond represents a condition on a trace.
+type cond interface {
+	match(t *trace) bool
+	String() string
+}
+
+type minCond time.Duration
+
+func (m minCond) match(t *trace) bool { return t.Elapsed >= time.Duration(m) }
+func (m minCond) String() string      { return fmt.Sprintf("≥%gs", time.Duration(m).Seconds()) }
+
+type errorCond struct{}
+
+func (e errorCond) match(t *trace) bool { return t.IsError }
+func (e errorCond) String() string      { return "errors" }
+
+type traceList []*trace
+
+// Free calls unref on each element of the list.
+func (trl traceList) Free() {
+	for _, t := range trl {
+		t.unref()
+	}
+}
+
+// traceList may be sorted in reverse chronological order.
+func (trl traceList) Len() int           { return len(trl) }
+func (trl traceList) Less(i, j int) bool { return trl[i].Start.After(trl[j].Start) }
+func (trl traceList) Swap(i, j int)      { trl[i], trl[j] = trl[j], trl[i] }
+
+// An event is a timestamped log entry in a trace.
+type event struct {
+	When       time.Time
+	Elapsed    time.Duration // since previous event in trace
+	NewDay     bool          // whether this event is on a different day to the previous event
+	Recyclable bool          // whether this event was passed via LazyLog
+	What       interface{}   // string or fmt.Stringer
+	Sensitive  bool          // whether this event contains sensitive information
+}
+
+// WhenString returns a string representation of the elapsed time of the event.
+// It will include the date if midnight was crossed.
+func (e event) WhenString() string {
+	if e.NewDay {
+		return e.When.Format("2006/01/02 15:04:05.000000")
+	}
+	return e.When.Format("15:04:05.000000")
+}
+
+// discarded represents a number of discarded events.
+// It is stored as *discarded to make it easier to update in-place.
+type discarded int
+
+func (d *discarded) String() string {
+	return fmt.Sprintf("(%d events discarded)", int(*d))
+}
+
+// trace represents an active or complete request,
+// either sent or received by this program.
+type trace struct {
+	// Family is the top-level grouping of traces to which this belongs.
+	Family string
+
+	// Title is the title of this trace.
+	Title string
+
+	// Timing information.
+	Start   time.Time
+	Elapsed time.Duration // zero while active
+
+	// Trace information if non-zero.
+	traceID uint64
+	spanID  uint64
+
+	// Whether this trace resulted in an error.
+	IsError bool
+
+	// Append-only sequence of events (modulo discards).
+	mu     sync.RWMutex
+	events []event
+
+	refs     int32 // how many buckets this is in
+	recycler func(interface{})
+	disc     discarded // scratch space to avoid allocation
+
+	finishStack []byte // where finish was called, if DebugUseAfterFinish is set
+}
+
+func (tr *trace) reset() {
+	// Clear all but the mutex. Mutexes may not be copied, even when unlocked.
+	tr.Family = ""
+	tr.Title = ""
+	tr.Start = time.Time{}
+	tr.Elapsed = 0
+	tr.traceID = 0
+	tr.spanID = 0
+	tr.IsError = false
+	tr.events = nil
+	tr.refs = 0
+	tr.recycler = nil
+	tr.disc = 0
+	tr.finishStack = nil
+}
+
+// delta returns the elapsed time since the last event or the trace start,
+// and whether it spans midnight.
+// L >= tr.mu
+func (tr *trace) delta(t time.Time) (time.Duration, bool) {
+	if len(tr.events) == 0 {
+		return t.Sub(tr.Start), false
+	}
+	prev := tr.events[len(tr.events)-1].When
+	return t.Sub(prev), prev.Day() != t.Day()
+}
+
+func (tr *trace) addEvent(x interface{}, recyclable, sensitive bool) {
+	if DebugUseAfterFinish && tr.finishStack != nil {
+		buf := make([]byte, 4<<10) // 4 KB should be enough
+		n := runtime.Stack(buf, false)
+		log.Printf("net/trace: trace used after finish:\nFinished at:\n%s\nUsed at:\n%s", tr.finishStack, buf[:n])
+	}
+
+	/*
+		NOTE TO DEBUGGERS
+
+		If you are here because your program panicked in this code,
+		it is almost definitely the fault of code using this package,
+		and very unlikely to be the fault of this code.
+
+		The most likely scenario is that some code elsewhere is using
+		a requestz.Trace after its Finish method is called.
+		You can temporarily set the DebugUseAfterFinish var
+		to help discover where that is; do not leave that var set,
+		since it makes this package much less efficient.
+	*/
+
+	e := event{When: time.Now(), What: x, Recyclable: recyclable, Sensitive: sensitive}
+	tr.mu.Lock()
+	e.Elapsed, e.NewDay = tr.delta(e.When)
+	if len(tr.events) < cap(tr.events) {
+		tr.events = append(tr.events, e)
+	} else {
+		// Discard the middle events.
+		di := int((cap(tr.events) - 1) / 2)
+		if d, ok := tr.events[di].What.(*discarded); ok {
+			(*d)++
+		} else {
+			// disc starts at two to count for the event it is replacing,
+			// plus the next one that we are about to drop.
+			tr.disc = 2
+			if tr.recycler != nil && tr.events[di].Recyclable {
+				go tr.recycler(tr.events[di].What)
+			}
+			tr.events[di].What = &tr.disc
+		}
+		// The timestamp of the discarded meta-event should be
+		// the time of the last event it is representing.
+		tr.events[di].When = tr.events[di+1].When
+
+		if tr.recycler != nil && tr.events[di+1].Recyclable {
+			go tr.recycler(tr.events[di+1].What)
+		}
+		copy(tr.events[di+1:], tr.events[di+2:])
+		tr.events[cap(tr.events)-1] = e
+	}
+	tr.mu.Unlock()
+}
+
+func (tr *trace) LazyLog(x fmt.Stringer, sensitive bool) {
+	tr.addEvent(x, true, sensitive)
+}
+
+func (tr *trace) LazyPrintf(format string, a ...interface{}) {
+	tr.addEvent(&lazySprintf{format, a}, false, false)
+}
+
+func (tr *trace) SetError() { tr.IsError = true }
+
+func (tr *trace) SetRecycler(f func(interface{})) {
+	tr.recycler = f
+}
+
+func (tr *trace) SetTraceInfo(traceID, spanID uint64) {
+	tr.traceID, tr.spanID = traceID, spanID
+}
+
+func (tr *trace) SetMaxEvents(m int) {
+	// Always keep at least three events: first, discarded count, last.
+	if len(tr.events) == 0 && m > 3 {
+		tr.events = make([]event, 0, m)
+	}
+}
+
+func (tr *trace) ref() {
+	atomic.AddInt32(&tr.refs, 1)
+}
+
+func (tr *trace) unref() {
+	if atomic.AddInt32(&tr.refs, -1) == 0 {
+		if tr.recycler != nil {
+			// freeTrace clears tr, so we hold tr.recycler and tr.events here.
+			go func(f func(interface{}), es []event) {
+				for _, e := range es {
+					if e.Recyclable {
+						f(e.What)
+					}
+				}
+			}(tr.recycler, tr.events)
+		}
+
+		freeTrace(tr)
+	}
+}
+
+func (tr *trace) When() string {
+	return tr.Start.Format("2006/01/02 15:04:05.000000")
+}
+
+func (tr *trace) ElapsedTime() string {
+	t := tr.Elapsed
+	if t == 0 {
+		// Active trace.
+		t = time.Since(tr.Start)
+	}
+	return fmt.Sprintf("%.6f", t.Seconds())
+}
+
+func (tr *trace) Events() []event {
+	tr.mu.RLock()
+	defer tr.mu.RUnlock()
+	return tr.events
+}
+
+var traceFreeList = make(chan *trace, 1000) // TODO(dsymonds): Use sync.Pool?
+
+// newTrace returns a trace ready to use.
+func newTrace() *trace {
+	select {
+	case tr := <-traceFreeList:
+		return tr
+	default:
+		return new(trace)
+	}
+}
+
+// freeTrace adds tr to traceFreeList if there's room.
+// This is non-blocking.
+func freeTrace(tr *trace) {
+	if DebugUseAfterFinish {
+		return // never reuse
+	}
+	tr.reset()
+	select {
+	case traceFreeList <- tr:
+	default:
+	}
+}
+
+func elapsed(d time.Duration) string {
+	b := []byte(fmt.Sprintf("%.6f", d.Seconds()))
+
+	// For subsecond durations, blank all zeros before decimal point,
+	// and all zeros between the decimal point and the first non-zero digit.
+	if d < time.Second {
+		dot := bytes.IndexByte(b, '.')
+		for i := 0; i < dot; i++ {
+			b[i] = ' '
+		}
+		for i := dot + 1; i < len(b); i++ {
+			if b[i] == '0' {
+				b[i] = ' '
+			} else {
+				break
+			}
+		}
+	}
+
+	return string(b)
+}
+
+var pageTmpl = template.Must(template.New("Page").Funcs(template.FuncMap{
+	"elapsed": elapsed,
+	"add":     func(a, b int) int { return a + b },
+}).Parse(pageHTML))
+
+const pageHTML = `
+{{template "Prolog" .}}
+{{template "StatusTable" .}}
+{{template "Epilog" .}}
+
+{{define "Prolog"}}
+<html>
+	<head>
+	<title>/debug/requests</title>
+	<style type="text/css">
+		body {
+			font-family: sans-serif;
+		}
+		table#tr-status td.family {
+			padding-right: 2em;
+		}
+		table#tr-status td.active {
+			padding-right: 1em;
+		}
+		table#tr-status td.latency-first {
+			padding-left: 1em;
+		}
+		table#tr-status td.empty {
+			color: #aaa;
+		}
+		table#reqs {
+			margin-top: 1em;
+		}
+		table#reqs tr.first {
+			{{if $.Expanded}}font-weight: bold;{{end}}
+		}
+		table#reqs td {
+			font-family: monospace;
+		}
+		table#reqs td.when {
+			text-align: right;
+			white-space: nowrap;
+		}
+		table#reqs td.elapsed {
+			padding: 0 0.5em;
+			text-align: right;
+			white-space: pre;
+			width: 10em;
+		}
+		address {
+			font-size: smaller;
+			margin-top: 5em;
+		}
+	</style>
+	</head>
+	<body>
+
+<h1>/debug/requests</h1>
+{{end}} {{/* end of Prolog */}}
+
+{{define "StatusTable"}}
+<table id="tr-status">
+	{{range $fam := .Families}}
+	<tr>
+		<td class="family">{{$fam}}</td>
+
+		{{$n := index $.ActiveTraceCount $fam}}
+		<td class="active {{if not $n}}empty{{end}}">
+			{{if $n}}<a href="?fam={{$fam}}&b=-1{{if $.Expanded}}&exp=1{{end}}">{{end}}
+			[{{$n}} active]
+			{{if $n}}</a>{{end}}
+		</td>
+
+		{{$f := index $.CompletedTraces $fam}}
+		{{range $i, $b := $f.Buckets}}
+		{{$empty := $b.Empty}}
+		<td {{if $empty}}class="empty"{{end}}>
+		{{if not $empty}}<a href="?fam={{$fam}}&b={{$i}}{{if $.Expanded}}&exp=1{{end}}">{{end}}
+		[{{.Cond}}]
+		{{if not $empty}}</a>{{end}}
+		</td>
+		{{end}}
+
+		{{$nb := len $f.Buckets}}
+		<td class="latency-first">
+		<a href="?fam={{$fam}}&b={{$nb}}">[minute]</a>
+		</td>
+		<td>
+		<a href="?fam={{$fam}}&b={{add $nb 1}}">[hour]</a>
+		</td>
+		<td>
+		<a href="?fam={{$fam}}&b={{add $nb 2}}">[total]</a>
+		</td>
+
+	</tr>
+	{{end}}
+</table>
+{{end}} {{/* end of StatusTable */}}
+
+{{define "Epilog"}}
+{{if $.Traces}}
+<hr />
+<h3>Family: {{$.Family}}</h3>
+
+{{if or $.Expanded $.Traced}}
+  <a href="?fam={{$.Family}}&b={{$.Bucket}}">[Normal/Summary]</a>
+{{else}}
+  [Normal/Summary]
+{{end}}
+
+{{if or (not $.Expanded) $.Traced}}
+  <a href="?fam={{$.Family}}&b={{$.Bucket}}&exp=1">[Normal/Expanded]</a>
+{{else}}
+  [Normal/Expanded]
+{{end}}
+
+{{if not $.Active}}
+	{{if or $.Expanded (not $.Traced)}}
+	<a href="?fam={{$.Family}}&b={{$.Bucket}}&rtraced=1">[Traced/Summary]</a>
+	{{else}}
+	[Traced/Summary]
+	{{end}}
+	{{if or (not $.Expanded) (not $.Traced)}}
+	<a href="?fam={{$.Family}}&b={{$.Bucket}}&exp=1&rtraced=1">[Traced/Expanded]</a>
+        {{else}}
+	[Traced/Expanded]
+	{{end}}
+{{end}}
+
+{{if $.Total}}
+<p><em>Showing <b>{{len $.Traces}}</b> of <b>{{$.Total}}</b> traces.</em></p>
+{{end}}
+
+<table id="reqs">
+	<caption>
+		{{if $.Active}}Active{{else}}Completed{{end}} Requests
+	</caption>
+	<tr><th>When</th><th>Elapsed&nbsp;(s)</th></tr>
+	{{range $tr := $.Traces}}
+	<tr class="first">
+		<td class="when">{{$tr.When}}</td>
+		<td class="elapsed">{{$tr.ElapsedTime}}</td>
+		<td>{{$tr.Title}}</td>
+		{{/* TODO: include traceID/spanID */}}
+	</tr>
+	{{if $.Expanded}}
+	{{range $tr.Events}}
+	<tr>
+		<td class="when">{{.WhenString}}</td>
+		<td class="elapsed">{{elapsed .Elapsed}}</td>
+		<td>{{if or $.ShowSensitive (not .Sensitive)}}... {{.What}}{{else}}<em>[redacted]</em>{{end}}</td>
+	</tr>
+	{{end}}
+	{{end}}
+	{{end}}
+</table>
+{{end}} {{/* if $.Traces */}}
+
+{{if $.Histogram}}
+<h4>Latency (&micro;s) of {{$.Family}} over {{$.HistogramWindow}}</h4>
+{{$.Histogram}}
+{{end}} {{/* if $.Histogram */}}
+
+	</body>
+</html>
+{{end}} {{/* end of Epilog */}}
+`