removeItemAt method
Implementation
void removeItemAt(int position){
if(position > items.length - 1) return;
listKey.currentState?.removeItem(position, (_, animation) => animateItem(context, position, animation), duration: animateDuration);
sliverListKey.currentState?.removeItem(position, (_, animation) => animateItem(context, position, animation), duration: animateDuration);
items.removeAt(position);
}