code: public <H extends EventHandler> HandlerRegistration addHandler(GwtEvent.Type<H> type, final H handler) {
  		if (type != null && handler != null) {
  			return new LegacyHandlerWrapper(this.eventBus.addHandler(type, handler));
  		}
  		return null;
  	}
docs: Adds a handler.
  
  @param <H> The type of handler
  @param type the event type associated with this handler
  @param handler the handler
  @return the handler registration, can be stored in order to remove the handler later