private function buildRSVPActions(PhabricatorCalendarEvent $event)
 {
     $viewer = $this->getViewer();
     $id = $event->getID();
     $is_pending = $event->isRSVPInvited($viewer->getPHID());
     if (!$is_pending) {
         return array();
     }
     $decline_button = id(new PHUIButtonView())->setTag('a')->setIcon('fa-times grey')->setHref($this->getApplicationURI("/event/decline/{$id}/"))->setWorkflow(true)->setText(pht('Decline'));
     $accept_button = id(new PHUIButtonView())->setTag('a')->setIcon('fa-check green')->setHref($this->getApplicationURI("/event/accept/{$id}/"))->setWorkflow(true)->setText(pht('Accept'));
     return array($decline_button, $accept_button);
 }