public function pagedResultResponse($key = null)
    {
        $cookie = null;
        $estimated = null;

        @ldap_control_paged_result_response($this->link, $this->resource, $cookie, $estimated);

        switch ($key) {
            case 'cookie':
                return $cookie;

            case 'estimated':
                return $estimated;

            default:
                return [ 'cookie' => $cookie, 'estimated' => $estimated ];
        }
    }