    @Test
    public void create() throws ExecutionException, InterruptedException {

        Flowable<Integer> flowable = Flowable.fromArray(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
                .subscribeOn(Schedulers.computation());

        List<String> list = ReactiveStreams.fromPublisher(flowable)
                .filter(i -> i < 4)
                .flatMapIterable(this::duplicate)
                .flatMapCompletionStage(this::asString)
                .toList()
                .run().toCompletableFuture().get();

        assertThat(list).containsExactly("1", "1", "2", "2", "3", "3");
    }