code: public static void subscribe(Object object) throws IllegalStateException {
          if (!sIsInitialized) {
              throw new IllegalStateException("Wings must be initialized. See Wings#init().");
          }
          WingsInjector.getBus().register(object);
      }
docs: Subscribes to link state changes of the endpoints. The subscribing {@link java.lang.Object} must
  have one or more {@link com.squareup.otto.Subscribe}-annotated methods, each taking a single
  parameter that corresponds to the {@link com.groundupworks.wings.WingsEndpoint.LinkEvent} subclass of the
  endpoint subscribed to.
  <p/>
  Upon subscription, the subscriber will immediately receive an event with the current link state
  even though the link state did not actually change. This initial value allows the subscriber
  to reflect the initial link state in the ui.
  
  @param object the {@link java.lang.Object} subscribing to the link state changes of the endpoints.
  @throws IllegalStateException Wings must be initialized. See {@link Wings#init(IWingsModule, Class[])}.