/**
  * update all flags of folder
  * 
  * @param Felamimail_Backend_ImapProxy $imap
  * @param Felamimail_Model_Folder $folder
  */
 protected function _updateAllFlags($imap, Felamimail_Model_Folder $folder)
 {
     if (Tinebase_Core::isLogLevel(Zend_Log::DEBUG)) {
         Tinebase_Core::getLogger()->debug(__METHOD__ . '::' . __LINE__ . ' Get all flags for folder');
     }
     $flags = $imap->getFlags(1, INF);
     for ($i = $folder->cache_totalcount; $i > 0; $i -= $this->_flagSyncCountPerStep) {
         $firstMessageSequence = $i - $this->_flagSyncCountPerStep >= 0 ? $i - $this->_flagSyncCountPerStep : 0;
         $messagesWithFlags = $this->_backend->getFlagsForFolder($folder->getId(), $firstMessageSequence, $this->_flagSyncCountPerStep);
         $this->_setFlagsOnCache($flags, $folder, $messagesWithFlags);
         if (!$this->_timeLeft()) {
             break;
         }
     }
 }