code: @Override
      public void start() throws Exception {
  
          if (dependency == null) {
              throw new IllegalStateException("Dependency was not injected!");
          }
  
          vertx.eventBus().consumer(EB_ADDRESS, this);
  
          super.start();
      }
docs: If your verticle does a simple, synchronous start-up then override this method and put your start-up
  code in there.
  
  @throws Exception