code: public <T> T addMaybeStartStartCloseInstance(T o, Stage stage) throws Exception
    {
      addMaybeStartHandler(new StartCloseHandler(o), stage);
      return o;
    }
docs: Adds an instance with a start() and/or close() method to the Lifecycle and starts it if the lifecycle has
  already been started.
  
  @param o     The object to add to the lifecycle
  @param stage The stage to add the lifecycle at
  
  @throws Exception {@link Lifecycle#addMaybeStartHandler(Handler, Stage)}