Provide old elements via ObservableList.LocalChange.Update

[SkytAsul]

When listening to changes from an ObservableList, we get a Change instance.
If this Change is a Change.Update instance, we can use Change.Update#getLocalChanges() to get local changes.
Local changes can be 3 subtypes : Removal, Insertion or Update.
In the case a local change is an Update, how to get the items that were previously at the place the new items got set? Using LocalChange#getElements() returns the items added, not the one that were before.