Cancellable
public protocol Cancellable
Represents a cancellation handler over an asynchronous operation. Cancellation may be immediate or simply requested to happen sometime in the future.
A typical usage for Cancellable
is to return it from the asynchronous completion-based API.
let cancellable = asynchronousFunction(completion: completion)
if shouldCancel {
cancellable.cancel()
}
Note
Cancellable
implementation must support thread-safety and guarantee that
after calling cancel()
the cancellation happens only once.
Cancels scheduled operation or does nothing if the operation is finished before the call.
Note
Subsequent calls shouldn’t do anything.Declaration
Swift
func cancel()