code: @Resource(name = "cxf")
     public final void setBus(Bus bus)
     {
        assert this.bus == null || this.bus == bus;
        this.bus = bus;
        if (bus != null)
        {
           bus.setExtension(this, UndertowServerEngineFactory.class);
           lifeCycleManager = bus.getExtension(BusLifeCycleManager.class);
           if (null != lifeCycleManager)
           {
              lifeCycleManager.registerLifeCycleListener(this);
           }
        }
     }
docs: This call is used to set the bus. It should only be called once.
  @param bus