cancel()
Notifies the system that user interactions canceled the transition.
Declaration
func cancel()Discussion
This is a convenience method that calls through to the cancelInteractiveTransition() method of the context object.
While tracking user interactions, your gesture recognizer or event-handling code would call this method when interactions suggest that the user wants to cancel or abort the view controller transition. For example, if the user reverses the swipe direction and then touch events end, suggesting that the user decided against the transition, you would call this method.