loadOnce method

@override Future<ApiCollectionModel<T>> loadOnce()

If the data is empty, load is performed only once.

In other cases, the value is returned as is.

Use isEmpty to determine whether the file is empty or not.

Implementation

@override
Future<ApiCollectionModel<T>> loadOnce() async {
  if (!loaded) {
    loaded = true;
    return load();
  }
  return this;
}