@Test
public void fusionClear() {

    Flowable.fromIterable(Arrays.asList(1, 2, 3))
    .subscribe(new FlowableSubscriber<Integer>() {
        @Override
        public void onSubscribe(Subscription d) {
            @SuppressWarnings("unchecked")
            QueueSubscription<Integer> qd = (QueueSubscription<Integer>)d;
            qd.requestFusion(QueueFuseable.ANY);
            try {
                assertEquals(1, qd.poll().intValue());
            } catch (Throwable ex) {
                fail(ex.toString());
            }
            qd.clear();
            try {
                assertNull(qd.poll());
            } catch (Throwable ex) {
                fail(ex.toString());
            }
        }
        @Override
        public void onNext(Integer value) {
        }
        @Override
        public void onError(Throwable e) {
        }
        @Override
        public void onComplete() {
        }
    });
}