...
@override
void dispose() {
  // Remove the app lifecycle observer.
  WidgetsBinding.instance.removeObserver(this);
  // Stop location updates when the widget is disposed.
  _locationDataSource.stop();
  super.dispose();
}
	...
	@override
	void dispose() {
	// Remove the app lifecycle observer.
	WidgetsBinding.instance.removeObserver(this);
	// Stop location updates when the widget is disposed.
	_locationDataSource.stop();
	super.dispose();
	}