protected function _createUniqueId()
    {
        $id = '';
        $id .= function_exists('microtime') ? microtime(true) : (time() . ' ' . rand(0, 100000));
        $id .= '.' . (function_exists('posix_getpid') ? posix_getpid() : rand(50, 65535));
        $id .= '.' . php_uname('n');

        return $id;
    }