Replaying and caching

Multicasting also allows caching values that are shared across multiple observers. This may sound surprising, but when you think about it long enough, you may realize this makes sense. If we are sharing data across multiple observers, it makes sense that any caching feature would be shared across observers too.

Replaying and caching data is a multicasting activity, and we will explore now how to do it safely and efficiently with RxJava.

Replaying

The replay() operator is a powerful way to hold onto previous emissions and re-emit them when a new Observer comes in. It returns ConnectableObservable, which both multicasts emissions and emits previous emissions. It emits the cached values immediately when...