T - the source Single's value typeR - the transformed Single's value typepublic static interface Single.Transformer<T,R> extends Func1<Single<T>,Single<R>>
Single.compose(rx.Single.Transformer<? super T, ? extends R>).
Transformer<Integer, Integer> transformer = s ->
s.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread());
Single.just(1)
.compose(transformer)
.subscribe(System.out::println);