moveOffset method
Implementation
void moveOffset(double offset) {
if (_sliverListController == null || _animationController == null) {
return;
}
_animation = Tween<double>(begin: _currentPosition, end: offset).animate(
CurvedAnimation(parent: _animationController!, curve: Curves.ease),
);
_animationController!.reset();
_animationController!.forward();
_currentPosition = offset;
}