diff --git a/vendor/github.com/coreos/etcd/proxy/grpcproxy/adapter/chan_stream.go b/vendor/github.com/coreos/etcd/proxy/grpcproxy/adapter/chan_stream.go
new file mode 100644
index 0000000..82e3411
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/proxy/grpcproxy/adapter/chan_stream.go
@@ -0,0 +1,165 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package adapter
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+)
+
+// chanServerStream implements grpc.ServerStream with a chanStream
+type chanServerStream struct {
+	headerc  chan<- metadata.MD
+	trailerc chan<- metadata.MD
+	grpc.Stream
+
+	headers []metadata.MD
+}
+
+func (ss *chanServerStream) SendHeader(md metadata.MD) error {
+	if ss.headerc == nil {
+		return errAlreadySentHeader
+	}
+	outmd := make(map[string][]string)
+	for _, h := range append(ss.headers, md) {
+		for k, v := range h {
+			outmd[k] = v
+		}
+	}
+	select {
+	case ss.headerc <- outmd:
+		ss.headerc = nil
+		ss.headers = nil
+		return nil
+	case <-ss.Context().Done():
+	}
+	return ss.Context().Err()
+}
+
+func (ss *chanServerStream) SetHeader(md metadata.MD) error {
+	if ss.headerc == nil {
+		return errAlreadySentHeader
+	}
+	ss.headers = append(ss.headers, md)
+	return nil
+}
+
+func (ss *chanServerStream) SetTrailer(md metadata.MD) {
+	ss.trailerc <- md
+}
+
+// chanClientStream implements grpc.ClientStream with a chanStream
+type chanClientStream struct {
+	headerc  <-chan metadata.MD
+	trailerc <-chan metadata.MD
+	*chanStream
+}
+
+func (cs *chanClientStream) Header() (metadata.MD, error) {
+	select {
+	case md := <-cs.headerc:
+		return md, nil
+	case <-cs.Context().Done():
+	}
+	return nil, cs.Context().Err()
+}
+
+func (cs *chanClientStream) Trailer() metadata.MD {
+	select {
+	case md := <-cs.trailerc:
+		return md
+	case <-cs.Context().Done():
+		return nil
+	}
+}
+
+func (cs *chanClientStream) CloseSend() error {
+	close(cs.chanStream.sendc)
+	return nil
+}
+
+// chanStream implements grpc.Stream using channels
+type chanStream struct {
+	recvc  <-chan interface{}
+	sendc  chan<- interface{}
+	ctx    context.Context
+	cancel context.CancelFunc
+}
+
+func (s *chanStream) Context() context.Context { return s.ctx }
+
+func (s *chanStream) SendMsg(m interface{}) error {
+	select {
+	case s.sendc <- m:
+		if err, ok := m.(error); ok {
+			return err
+		}
+		return nil
+	case <-s.ctx.Done():
+	}
+	return s.ctx.Err()
+}
+
+func (s *chanStream) RecvMsg(m interface{}) error {
+	v := m.(*interface{})
+	for {
+		select {
+		case msg, ok := <-s.recvc:
+			if !ok {
+				return grpc.ErrClientConnClosing
+			}
+			if err, ok := msg.(error); ok {
+				return err
+			}
+			*v = msg
+			return nil
+		case <-s.ctx.Done():
+		}
+		if len(s.recvc) == 0 {
+			// prioritize any pending recv messages over canceled context
+			break
+		}
+	}
+	return s.ctx.Err()
+}
+
+func newPipeStream(ctx context.Context, ssHandler func(chanServerStream) error) chanClientStream {
+	// ch1 is buffered so server can send error on close
+	ch1, ch2 := make(chan interface{}, 1), make(chan interface{})
+	headerc, trailerc := make(chan metadata.MD, 1), make(chan metadata.MD, 1)
+
+	cctx, ccancel := context.WithCancel(ctx)
+	cli := &chanStream{recvc: ch1, sendc: ch2, ctx: cctx, cancel: ccancel}
+	cs := chanClientStream{headerc, trailerc, cli}
+
+	sctx, scancel := context.WithCancel(ctx)
+	srv := &chanStream{recvc: ch2, sendc: ch1, ctx: sctx, cancel: scancel}
+	ss := chanServerStream{headerc, trailerc, srv, nil}
+
+	go func() {
+		if err := ssHandler(ss); err != nil {
+			select {
+			case srv.sendc <- err:
+			case <-sctx.Done():
+			case <-cctx.Done():
+			}
+		}
+		scancel()
+		ccancel()
+	}()
+	return cs
+}