title: How to set several message handlers for channel in spring integration DSL?
body: <p>I wrote my first spring integration application which reads data from spring RSS and logs it into console:</p>
  
  <pre><code>@Configuration
  @EnableIntegration
  @IntegrationComponentScan
  public class DslConfig {
  
      @Bean
      public IntegrationFlow feedFlow() throws MalformedURLException {
          return IntegrationFlows.from(inBoundFeedDataAdapter(), configurer -&gt; configurer.poller(Pollers.fixedDelay(1000)))
                  .channel(newsChannel())
                  .transform(source -&gt; {
                      SyndEntry e = ((SyndEntry) source);
                      return e.getTitle() + " " + e.getLink();
                  })
                  .handle(messageHandler())
                  .get();
      }
  
      @Bean
      public FeedEntryMessageSourceSpec inBoundFeedDataAdapter() throws MalformedURLException {
          return Feed.inboundAdapter(new URL("https://spring.io/blog.atom"), "some_key");
      }
  
      @Bean
      public MessageChannel newsChannel() {
          return new DirectChannel();
      }
  
      @Bean
      public MessageHandler messageHandler() {
          return System.out::println;
      }
  }
  </code></pre>
  
  <p>But I have no idea how can I add one additional handler for writing result into file.</p>
  
  <p>How can I achieve it ?</p>
  
  <p><strong>Additional questions:</strong></p>
  
  <p>What is the meaning of metadata key ?</p>