message: Add provenance tag
diff: @@ -93,6 +93,7 @@ std::shared_ptr<TOpType> ConstructNgNode(const std::string& op_name,
  TArg&&... Args) {
  auto ng_node = std::make_shared<TOpType>(std::forward<TArg>(Args)...);
  ng_node->set_friendly_name(op_name);
  + ng_node->add_provenance_tag(op_name);
  return ng_node;
  }
  