message: Fix use-after-free bug.
diff: @@ -680,7 +680,7 @@ void TFE_Py_TapeRecordOperation(PyObject* tape, PyObject* op_type,
  }
  }
  Py_DECREF(seq);
  - char* op_type_str = nullptr;
  + string op_type_str;
  if (PyBytes_Check(op_type)) {
  op_type_str = PyBytes_AsString(op_type);
  } else if (PyUnicode_Check(op_type)) {
  