private function buildHeaderView(PhabricatorCalendarEvent $event)
 {
     $viewer = $this->getViewer();
     $id = $event->getID();
     if ($event->isCancelledEvent()) {
         $icon = 'fa-ban';
         $color = 'red';
         $status = pht('Cancelled');
     } else {
         $icon = 'fa-check';
         $color = 'bluegrey';
         $status = pht('Active');
     }
     $header = id(new PHUIHeaderView())->setUser($viewer)->setHeader($event->getName())->setStatus($icon, $color, $status)->setPolicyObject($event)->setHeaderIcon($event->getIcon());
     foreach ($this->buildRSVPActions($event) as $action) {
         $header->addActionLink($action);
     }
     return $header;
 }