- [E? futureValue]
Returns a future that handles the onDone and onError callbacks.
This method overwrites the existing onDone and onError callbacks with new ones that complete the returned future.
In case of an error the subscription will automatically cancel (even
when it was listening with
cancelOnError set to
In case of a
done event the future completes with the given
futureValue is omitted, the value
null as E is used as a default.
E is not nullable, this will throw immediately when asFuture
Future<E> asFuture<E>([E? futureValue]);