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

Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/coreos/etcd/rafthttp/coder.go b/vendor/github.com/coreos/etcd/rafthttp/coder.go
new file mode 100644
index 0000000..86ede97
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/rafthttp/coder.go
@@ -0,0 +1,27 @@
+// Copyright 2015 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 rafthttp
+
+import "github.com/coreos/etcd/raft/raftpb"
+
+type encoder interface {
+	// encode encodes the given message to an output stream.
+	encode(m *raftpb.Message) error
+}
+
+type decoder interface {
+	// decode decodes the message from an input stream.
+	decode() (raftpb.Message, error)
+}