code: public T messageType(String messageType) {
          this.messageType = messageType;
          getAction().setMessageType(messageType);
  
          if (getAction().getValidationContexts().isEmpty()) {
              getAction().getValidationContexts().add(headerValidationContext);
              getAction().getValidationContexts().add(xmlMessageValidationContext);
              getAction().getValidationContexts().add(jsonMessageValidationContext);
          }
  
          return self;
      }
docs: Sets a explicit message type for this receive action.
  @param messageType
  @return