code: @NonNull
      private static <T> ObservableTransformer<T, T> repeatAfterCompleted() {
          return observable -> observable.repeatWhen(completedNotification -> completedNotification);
      }
docs: A convenience function creating a transformer that will repeat the source observable whenever it will complete
  
  @param <T> the type of the transformed observable
  @return transformer that will emit observable that will never complete (source will be subscribed again)