Completion handlers for UITableView-based animations

[jenox]

I recently found myself in need of a completion handlers when using Differ to run an animation on UITableView. Differ is still using the beginUpdates()/endUpdates() APIs for UITableView which do not support completion handlers. However, since iOS 11, UITableView too supports performBatchUpdates(_:completion:).

I would love to see an overloaded animateRowChanges and animateRowAndSectionChanges which use the performBatchUpdates API and support a completion handler. We can obviously keep the old methods around to support older OSes. Is this something that you would be interested in having in this project, or is this something you already decided against?