listen method

void listen(
  1. dynamic listener(
    1. dynamic
    )
)

Implementation

void listen(Function(dynamic) listener) {
  try {
    _checkKey(_key, () => _items[_key]!.addListener(listener));
  } catch (e) {
    _items[_key] = _AccessorItem(null);
    _items[_key]!.addListener(listener);
  }
}