A type-erasing cancellable object that executes a provided closure when canceled.
- iOS 13.0+Beta
- macOS 10.15+Beta
- Mac Catalyst 13.0+Beta
- tvOS 13.0+Beta
- watchOS 6.0+Beta
- Xcode 11.0+Beta
Subscriber implementations can use this type to provide a “cancellation token” that makes it possible for a caller to cancel a publisher, but not to use the
Subscription object to request items.