set status before Finish in prefetch process

paddle/fluid/operators/detail/grpc_server.cc

@@ -168,9 +168,9 @@ class RequestPrefetch final : public RequestBase {
 
     SerializeToByteBuffer(out_var_name, outvar, *request_handler_->dev_ctx(),
                           &reply_);
+    status_ = FINISH;
     responder_.Finish(reply_, ::grpc::Status::OK,
                       reinterpret_cast<void*>(static_cast<intptr_t>(req_id_)));
-    status_ = FINISH;
   }
 
  protected:

paddle/fluid/operators/listen_and_serv_op.cc

@@ -247,7 +247,7 @@ void ListenAndServOp::RunImpl(const framework::Scope &scope,
   rpc_service_->RegisterRPC(detail::kRequestSend, request_send_handler_.get());
   rpc_service_->RegisterRPC(detail::kRequestGet, request_get_handler_.get());
   rpc_service_->RegisterRPC(detail::kRequestPrefetch,
-                            request_prefetch_handler_.get(), 1);
+                            request_prefetch_handler_.get());
 
   auto *optimize_block = Attr<framework::BlockDesc *>(kOptimizeBlock);
   auto *program = optimize_block->Program();