Clear receive message buffer when adding it, so that any reused buffer will...

Clear receive message buffer when adding it, so that any reused buffer will not appear when decoding fails.

src/cpp/common/call.cc

@@ -31,6 +31,7 @@
  *
  */
 
+#include <google/protobuf/message.h>
 #include <grpc/support/alloc.h>
 #include <grpc++/impl/call.h>
 #include <grpc++/client_context.h>
@@ -144,6 +145,7 @@ void CallOpBuffer::AddSendMessage(const google::protobuf::Message& message) {
 
 void CallOpBuffer::AddRecvMessage(google::protobuf::Message* message) {
   recv_message_ = message;
+  recv_message_->Clear();
 }
 
 void CallOpBuffer::AddClientSendClose() { client_send_close_ = true; }