observe method

@override Dispose observe(Listener<ListChange<T>> listener, { bool fireImmediately = false, })

Attach a listener to the changes happening in the list.

You can choose to receive the change notification immediately (with fireImmediately) or on the first change

Implementation

@override
Dispose observe(
  Listener<ListChange<T>> listener, {
  bool fireImmediately = false,
}) {
  if (fireImmediately == true) {
    final change = ListChange<T>(
      list: this,
      rangeChanges: <RangeChange<T>>[
        RangeChange(index: 0, newValues: toList(growable: false)),
      ],
    );
    listener(change);
  }

  return _listeners.add(listener);
}