doOnCancel method
inherited
Invokes the given callback function when the stream subscription is cancelled. Often called doOnUnsubscribe or doOnDispose in other implementations.
Example
final subscription = new Observable.timer(1, new Duration(minutes: 1))
.doOnCancel(() => print("hi"));
.listen(null);
subscription.cancel(); // prints "hi"
Implementation
Observable<T> doOnCancel(void onCancel()) =>
transform(DoStreamTransformer<T>(onCancel: onCancel));