dispose method

@override void dispose()

Disposes this ValueListenable. Successive calls to this method will be ignored.

The single source of truth for "is this disposed?" is WeakChangeNotifier.isDisposed. Subclasses must consult that getter rather than maintaining their own flag.

Implementation

@override
void dispose() {
  for (var parent in _parents) {
    parent._removeChild(this);
  }
  super.dispose();
}