[VOL-4291] Rw-core updates for gRPC migration

Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/coreos/etcd/proxy/grpcproxy/adapter/watch_client_adapter.go b/vendor/github.com/coreos/etcd/proxy/grpcproxy/adapter/watch_client_adapter.go
new file mode 100644
index 0000000..afe61e8
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/proxy/grpcproxy/adapter/watch_client_adapter.go
@@ -0,0 +1,66 @@
+// Copyright 2016 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"
+	"errors"
+
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
+	"google.golang.org/grpc"
+)
+
+var errAlreadySentHeader = errors.New("adapter: already sent header")
+
+type ws2wc struct{ wserv pb.WatchServer }
+
+func WatchServerToWatchClient(wserv pb.WatchServer) pb.WatchClient {
+	return &ws2wc{wserv}
+}
+
+func (s *ws2wc) Watch(ctx context.Context, opts ...grpc.CallOption) (pb.Watch_WatchClient, error) {
+	cs := newPipeStream(ctx, func(ss chanServerStream) error {
+		return s.wserv.Watch(&ws2wcServerStream{ss})
+	})
+	return &ws2wcClientStream{cs}, nil
+}
+
+// ws2wcClientStream implements Watch_WatchClient
+type ws2wcClientStream struct{ chanClientStream }
+
+// ws2wcServerStream implements Watch_WatchServer
+type ws2wcServerStream struct{ chanServerStream }
+
+func (s *ws2wcClientStream) Send(wr *pb.WatchRequest) error {
+	return s.SendMsg(wr)
+}
+func (s *ws2wcClientStream) Recv() (*pb.WatchResponse, error) {
+	var v interface{}
+	if err := s.RecvMsg(&v); err != nil {
+		return nil, err
+	}
+	return v.(*pb.WatchResponse), nil
+}
+
+func (s *ws2wcServerStream) Send(wr *pb.WatchResponse) error {
+	return s.SendMsg(wr)
+}
+func (s *ws2wcServerStream) Recv() (*pb.WatchRequest, error) {
+	var v interface{}
+	if err := s.RecvMsg(&v); err != nil {
+		return nil, err
+	}
+	return v.(*pb.WatchRequest), nil
+}