public static function sendWithXSendfile ( $filePath ){
      if ( stripos($_SERVER['SERVER_SOFTWARE'], 'nginx') !== FALSE ){
        $fallback = true;
        $config =& CKFinder_Connector_Core_Factory::getInstance("Core_Config");
        $XSendfileNginx = $config->getXSendfileNginx();
        foreach ( $XSendfileNginx as $location => $root){
          if ( false !== stripos($filePath , $root) ){
            $fallback = false;
            $filePath = str_ireplace($root,$location,$filePath);
            header("X-Accel-Redirect: ".$filePath); // Nginx
            break;
          }
        }
        // fallback to standar method
        if ( $fallback ){
          CKFinder_Connector_Utils_FileSystem::readfileChunked($filePath);
        }
      } elseif ( stripos($_SERVER['SERVER_SOFTWARE'], 'lighttpd/1.4') !== FALSE ){
        header("X-LIGHTTPD-send-file: ".$filePath); // Lighttpd v1.4
      } else {
        header("X-Sendfile: ".$filePath); // Apache, Lighttpd v1.5, Cherokee
      }
    }