OnBackpressureBuffer.java

Flowable.range(0, 1000000)
    .onBackpressureBuffer()
    .observeOn(Schedulers.computation())
    .subscribe(new FlowableSubscriber<Integer>() {
        @Override
        public void onSubscribe(Subscription s) {

        }
        @Override
        public void onNext(Integer integer) {
            Log.d(TAG, "onNext: " + integer);
        }
        @Override
        public void onError(Throwable t) {
            Log.e(TAG, "onError: ", t);
        }
        @Override
        public void onComplete() {

        }
    });