Changes the cancelled state of the receiver to indicate that it should exit.
- iOS 2.0+
- macOS 10.5+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
The semantics of this method are the same as those used for
NSOperation. This method sets state information in the receiver that is then reflected by the
cancelled property. Threads that support cancellation should periodically call the
cancelled method to determine if the thread has in fact been cancelled, and exit if it has been.
For more information about cancellation and operation objects, see