/**
  * Gets the number of unread messages in the inbox of the current user
  *
  * @return int
  */
 public function countInboxNew()
 {
     if (!array_key_exists('count_inbox_new', $this->cache)) {
         $participant = $this->participantProvider->getAuthenticatedParticipant();
         $this->cache['count_inbox_new'] = $this->provider->countInboxNewThreads($participant);
     }
     return $this->cache['count_inbox_new'];
 }