tensorflow::mutex_lock c(graph->mu);
  const auto& debug_str = graph->graph.ToGraphDefDebug().DebugString();
  *len = debug_str.size();
  char* ret = static_cast<char*>(malloc(*len + 1));
  memcpy(ret, debug_str.c_str(), *len + 1);
  return ret;
}

char* TF_FunctionDebugString(TF_Function* func, size_t* len) {
  const auto& debug_str = DebugString(func->record->fdef());
  *len = debug_str.size();

    *   `partial_tensor_shape.h` -> `../framework/partial_tensor_shape.h`
    *   `tensorflow_server.h` deleted
*   For C++ API users: `TensorShape::ShortDebugString` has been renamed to
    `DebugString`, and the previous `DebugString` behavior is gone (it was
    needlessly verbose and produced a confusing empty string for scalars).
*   `GraphOptions.skip_common_subexpression_elimination` has been removed. All