public IObservable <Unit> Close()
{
//if (_closing)
// return Observable.Empty<Unit>();
_openTween?.Kill();
_closeTween = transform.DOScale(Vector3.zero, _duration);
_closing = true;
return(_closeTween.AsObservable()
.Where(x => x == DotweenState.Complete)
.Select(_ => Unit.Default));
//.AsUnitObservable();
}