DefaultFluentProducerTemplate is not thread safe

I think we have rediscovered the CAMEL-10820 bug. A body of one request gets replaced with a body of proceeding request, in our case we use request() method instead of asyncSend().

We use camel together with spring-boot. Consider following code:

@Service
public class UseCamelService {

   private FluentProducerTemplate producer;

   @Autowired
   public UseCamelService(FluentProducerTemplate producer) {
      this.producer = producer;
   }

   public String getValueFromCamel(String body) {
      return producer.to("route").withBody(body).request(String.class);
   }

}

If UseCamelService.getValueFromCamel() gets called from two different threads it is possible for the latter one to override the body of the first one.