public function getItemAt(index:int, prefetch:int = 0):Object
Gets the item at the specified index.
Object — The item at that index, or null if there is
By definition, this is supposed to return null if the item
does not exist. When I test
(ArrayCollection.getItemAt(invalidIndex) == null) it never returns
true. However, if I trace that same index, it will break. How can I
know if there is an item at that index or not?