Use case

I'm creating widget, like free-transform in photoshop
I have main draggable (big rectangle) and small draggable (small circles) in each corner
To be able to update all their positions I had to add onDragUpdate callback to Draggable

Proposal

Draggable should have parameter Function(DragUpdateDetails) onDragUpdate

I can provide a PR if any maintainer approve this as valid feature