$content=theme('maintenance_page',array('content'=>filter_xss_admin(variable_get('maintenance_mode_message',t('@site is currently under maintenance. We should be back shortly. Thank you for your patience.',array('@site'=>variable_get('site_name','Drupal')))))));
$response=newResponse('Service unavailable',503);
$response->setContent($content);
$event->setResponse($response);
}
}
/**
* Registers the methods in this class that should be listeners.