我有一个非常简单的演员，只是打印的数字：-

public class PrintLineActor extends AbstractLoggingActor {

  @Override
  public Receive createReceive() {
    return receiveBuilder()
        .match(Integer.class, i -> {
          System.out.println("Processing: " + i);
          sender().tell(i, self());
        }).build();
  }
}

现在，我有一个流来打印偶数，直到遇到奇数元素：-

@Test
  public void streamsTest() throws Exception {

    ActorSystem system = ActorSystem.create("testSystem");
    ActorRef printActor = system.actorOf(Props.create(PrintLineActor.class));

    Integer[] intArray = new Integer[]{2,4,6,8,9,10,12};
    CompletionStage<List<Integer>> result = Source.from(Arrays.asList(intArray))
        .ask(1, printActor, Integer.class, Timeout.apply(10, TimeUnit.SECONDS))
        .takeWhile(i -> i != 9)
        .runWith(Sink.seq(), ActorMaterializer.create(system));

    List<Integer> result1 = result.toCompletableFuture().get();
    System.out.println("Result :- ");
    result1.forEach(System.out::println);
  }

我不期望任何在9之后的元素被处理，也就是被发送到actor。但是，我看到数字“10”也被actor处理（而不是12），如下面的输出所示

Processing: 2
Processing: 4
Processing: 6
Processing: 8
Processing: 9
Processing: 10 //WHY IS THIS BEING PROCESSED BY ACTOR??

Result :- 
2
4
6
8

为什么10正在被演员处理？如何阻止？
编辑：
我试过通过记录事件的时间戳来调试，只是为了看看在9实际完成之前是否正在处理10，但没有，10是在9完全处理之后进行的。下面是日志：-

Before Ask: 2 in 1596035906509
Processing inside Actor: 2 at 1596035906509
Inside TakeWhile 2 at  in 1596035906509

Before Ask: 4 in 1596035906609
Processing inside Actor: 4 at 1596035906610
Inside TakeWhile 4 at  in 1596035906610

Before Ask: 6 in 1596035906712
Processing inside Actor: 6 at 1596035906712
Inside TakeWhile 6 at  in 1596035906712

Before Ask: 8 in 1596035906814
Processing inside Actor: 8 at 1596035906814
Inside TakeWhile 8 at  in 1596035906815

Before Ask: 9 in 1596035906915
Processing inside Actor: 9 at 1596035906915
Inside TakeWhile 9 at  in 1596035906916

Before Ask: 10 in 1596035907017 //so 10 is taken much after the 9 is processed fully
Processing inside Actor: 10 at 1596035907017

Result :- 
2
4
6
8

另外，如果我用一个direct.map（print..）替换.ask，那么10就不会被打印出来。所以为什么当涉及actor.ask时会发生这种情况，这对我来说很奇怪。