CancelableCompleter<T> constructor
- FutureOr onCancel()?,
Creates a new completer for a CancelableOperation.
The cancelable operation can be completed using complete or completeError.
The onCancel
function is called if the operation is canceled,
by calling CancelableOperation.cancel
before the operation has completed.
If onCancel
returns a Future,
that future is also returned by CancelableOperation.cancel.
The onCancel
function will be called at most once.
Implementation
CancelableCompleter({FutureOr Function()? onCancel}) : _onCancel = onCancel;