Motivation:
The need of cascade from a Future to a Promise exists. We should add some default implementation for it.
Modifications:
- Merge PromiseNotifier into Futures
- Add default cascadeTo(...) methods to Future
- Add tests to FuturesTest
- Replace usage of PromiseNotifier with Future.cascadeTo
- Use combination of map(...) and cascadeTo(...) in *Bootstrap to reduce code duplication
Result:
Provide default implementation of cascadeTo.