/// {@template flutter.material.inkwell.statesController}
  /// Represents the interactive "state" of this widget in terms of
  /// a set of [WidgetState]s, like [WidgetState.pressed] and
  /// [WidgetState.focused].
  ///
  /// Classes based on this one can provide their own
  /// [WidgetStatesController] to which they've added listeners.
  /// They can also update the controller's [WidgetStatesController.value]
  /// however, this may only be done when it's safe to call
  /// [State.setState], like in an event handler.
  /// {@endtemplate}
  final WidgetStatesController? statesController;