public function write($key, $vars)
    {
        $data   = serialize(array('changed' => time(), 'ip' => $this->ip, 'vars' => $vars));
        $result = $this->memcache->set($key, $data, MEMCACHE_COMPRESSED, $this->lifetime + 60);

        if ($this->debug) {
            $this->debug('set', $key, $data, $result);
        }

        return $result;
    }