subscribe method

void Function() subscribe(void listener(List<TSelected>))

Registers a listener without delivering an initial snapshot.

Implementation

void Function() subscribe(void Function(List<TSelected>) listener) {
  if (!hasListeners) {
    _update(notify: false);
    _unsubscribe = _client.mutationCache.subscribe((_) => _update());
  }
  return _listeners.add(listener, onRemoved: () {
    if (!hasListeners) {
      _unsubscribe?.call();
      _unsubscribe = null;
    }
  });
}