We need the right sequence number for the stream

server/rpc_stream.go

@@ -30,18 +30,16 @@ func (r *rpcStream) Send(msg interface{}) error {
 	r.Lock()
 	defer r.Unlock()
 
-	seq := r.seq
-	r.seq++
-
 	resp := response{
 		ServiceMethod: r.request.Method(),
-		Seq:           seq,
+		Seq:           r.seq,
 	}
 
 	err := r.codec.WriteResponse(&resp, msg, false)
 	if err != nil {
 		log.Println("rpc: writing response:", err)
 	}
+
 	return err
 }
 
@@ -57,6 +55,9 @@ func (r *rpcStream) Recv(msg interface{}) error {
 		return err
 	}
 
+	// we need to stay upto date with sequence numbers
+	r.seq = req.Seq
+
 	if err := r.codec.ReadRequestBody(msg); err != nil {
 		return err
 	}

server/rpcplus_server.go

@@ -277,6 +277,7 @@ func (s *service) call(ctx context.Context, server *server, sending *sync.Mutex,
 		context: ctx,
 		codec:   codec,
 		request: r,
+		seq:     req.Seq,
 	}
 
 	// Invoke the method, providing a new value for the reply.