title: Spring Cloud Stream @SendTo Annotation not working
body: <p>I'm using Spring Cloud Stream with Spring Boot. My application is very simple:</p>
  
  <p>ExampleService.class:</p>
  
  <pre><code>@EnableBinding(Processor1.class)
  @Service
  public class ExampleService {
  
      @StreamListener(Processor1.INPUT)
      @SendTo(Processor1.OUTPUT)
      public String dequeue(String message){
          System.out.println("New message: " + message);
          return message;
      }
  
      @SendTo(Processor1.OUTPUT)
      public String queue(String message){
          return message;
      }
  }
  </code></pre>
  
  <p>Procesor1.class:</p>
  
  <pre><code>public interface Processor1 {
  
      String INPUT = "input1";
      String OUTPUT = "output1";
  
      @Input(Processor1.INPUT)
      SubscribableChannel input1();
  
      @Output(Processor1.OUTPUT)
      MessageChannel output1();
  }
  </code></pre>
  
  <p>application.properties:</p>
  
  <pre><code>spring.cloud.stream.bindings.input1.destination=test_input
  spring.cloud.stream.bindings.input1.group=test_group
  spring.cloud.stream.bindings.input1.binder=binder1
  
  spring.cloud.stream.bindings.output1.destination=test_output
  spring.cloud.stream.bindings.output1.binder=binder1
  
  spring.cloud.stream.binders.binder1.type=rabbit
  </code></pre>
  
  <p>spring.cloud.stream.binders.binder1.environment.spring.rabbitmq.host=localhost</p>
  
  <p>Scenarios:</p>
  
  <p>1) When I push a message in 'test_input.test_group' queue, message is correctly printed and correctly sent to 'test_output' exchange. So ExampleService::dequeue works well.</p>
  
  <p>2) When I invoke ExampleService::queue method (from outside the class, in a test), message is never sent to 'test_output' exchange.</p>
  
  <p>I'm working with Spring Boot 2.0.6.RELEASE and Spring Cloud Stream 2.0.2.RELEASE.</p>
  
  <p>Anybody knows why scenario 2) is not working? Thanks in advance.</p>