title: No delay happening when sending messages between message channels
body: <p>I am new to Spring Integration DSL. Currently, i am trying to add a delay 
  between message channels- "ordersChannel" and "bookItemsChannel". But , the flow continues as though there is no delay. 
  Any help appreciated.
  Here is the code:</p>
  
  <pre><code>@Bean
  public IntegrationFlow ordersFlow() {
      return IntegrationFlows.from("ordersChannel")
              .split(new AbstractMessageSplitter() {
  
                  @Override
                  protected Object splitMessage(Message&lt;?&gt; message) {
  
                      return ((Order)message.getPayload()).getOrderItems();
                  }
              })
              .delay("normalMessage", new Consumer&lt;DelayerEndpointSpec&gt;() {
  
                  public void accept(DelayerEndpointSpec spec) {
                      spec.id("delayChannel");
                      spec.defaultDelay(50000000);
                      System.out.println("Going to delay");
                  }
              })
              .channel("bookItemsChannel")
              .get();
  }
  </code></pre>