### Question:
DataUploaderService { @Optional @Complexity(HARD) public Mono<Void> upload(Flux<OrderedByteBuffer> input) { throw new RuntimeException("Not implemented"); } DataUploaderService(HttpClient client); @Optional @Complexity(HARD) Mono<Void> upload(Flux<OrderedByteBuffer> input);  }### Answer:
@Test public void uploadTest() { TrickyHttpClient client = new TrickyHttpClient(); DataUploaderService service = new DataUploaderService(client); StepVerifier.withVirtualTime(() -> service.upload( Flux.range(0, 1000) .map(i -> new OrderedByteBuffer(i, ByteBuffer.allocate(i))) .window(100) .delayElements(Duration.ofMillis(1500)) .flatMap(Function.identity()) )) .expectSubscription() .thenAwait(Duration.ofSeconds(1000)) .verifyComplete(); verifyOrdered(client); verifyTimeout(client); }