dispose method

@override void dispose()

Called when this object is removed from the tree permanently.

Override this to clean up any resources held by this object (cancel timers, close streams, etc).

Implementation

@override
void dispose() {
  assert(
    _ticker == null || !_ticker!.isTicking,
    'SingleTickerProviderStateMixin.dispose called with an active ticker. '
    'Dispose your AnimationController before calling super.dispose().',
  );
  _ticker?.dispose();
  _ticker = null;
  super.dispose();
}