AnimatedItemBuilder typedef Null safety
context argument is the build context where the widget will be
index is the index of the item to be built, and the
animation is an Animation that should be used to animate an entry
transition for the widget that is built.
- AnimatedRemovedItemBuilder, a builder that is for removing items with animations instead of adding them.
typedef AnimatedItemBuilder = Widget Function(BuildContext context, int index, Animation<double> animation);