@PostConstruct and autowiring a MessageChannel

I'm having a problem with Spring Cloud Stream. The thing is that I have a bean that will write to Kafka as soon as it's created (method annotated with @PostConstruct), so I autowire the appropriate MessageChannel and set the destination and binder properties in application.yml. It goes like this:

@Component
@RequiredArgsConstructor
public class Sender
{
    private final MessageChannel output;

    @PostConstruct
    public void start()
    {
       output.send(new GenericMessage("Hello world");  
    }
}

And application.yml

spring:
    cloud:
        stream:
            bindings:
              output:
                destination: someData
                binder: kafka

I also have the following dependencies:

- spring-cloud-stream-reactive
- reactor-core
- spring-cloud-starter-stream-kafka

The project itself is starting, but I'm getting the following exception when trying to write to the output in start() method:

Caused by: org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers

Is it because Kafka binder didn't manage to bind the channel yet or what? If so, what is the alternative way to this.

Thanks in advance.