changed Touches
The touch points that contributed to the event.
Meaning of these points varies depending on the event type.
- For TouchStarted, it is a list of the touches that became active with this event.
- For TouchMoved, it is a list of the touches that have changed since the last event.
- For TouchCanceled and TouchEnded, it is a list of the touches that have just been removed, and no longer present on the screen.