protected function _write_memcached($session_id, $payload)
	{
		// write it to the memcached server
		if ($this->memcached->set($this->config['cookie_name'].'_'.$session_id, $payload, $this->config['expiration_time']) === false)
		{
			throw new \FuelException('Memcached returned error code "'.$this->memcached->getResultCode().'" on write. Check your configuration.');
		}
	}