Indicates whether the receiver is tracking work that has been cancelled.
- iOS 7.0+
- macOS 10.9+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
NSProgress is KVO-compliant for this property, sending notifications on the same thread that updates the property.
If the receiver has a parent that has already been cancelled, the receiver will also report being cancelled.