dismiss method
Animate to dismiss the notification.
Implementation
@override
Future<void> dismiss({double currentPosition = 0.0}) async {
currentAnimation = Tween(
begin: currentPosition - _notificationHeight,
end: -_notificationHeight,
).chain(_defaultCurve).animate(this);
dragDistance = 0.0;
await forward(from: 0.0);
currentAnimation = null;
}