addAll method
Adds item
to cart. This and removeAll are the only ways to modify the
cart from the outside.
Implementation
void addAll(List<Message> list, {bool scrollTo = false}) {
_items.insertAll(0, list.reversed);
// This call tells the widgets that are listening to this model to rebuild.
if (scrollTo) {
initialScrollPosition = _items.length - 1;
}
notifyListeners();
}