}

bool ModularFileSystem::FilesExist(const std::vector<std::string>& files,
                                   TransactionToken* token,
                                   std::vector<Status>* status) {
  if (ops_->paths_exist == nullptr)
    return FileSystem::FilesExist(files, token, status);

  std::vector<char*> translated_names;
  translated_names.reserve(files.size());
  for (int i = 0; i < files.size(); i++)

  };
  return tensorflow::unwrap(cancellation_manager)
      ->RegisterCallbackWithErrorLogging(token, callback, callback_name);
}

bool TFE_CancellationManagerDeregisterCallback(
    TFE_CancellationManager* cancellation_manager,
    TFE_CancellationToken token) {
  return tensorflow::unwrap(cancellation_manager)->DeregisterCallback(token);
}

bool TFE_CancellationManagerTryDeregisterCallback(