直接在Gateway.php写代码使用redis，报错

<?php
/**
 * This file is part of workerman.
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the MIT-LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @author    walkor<walkor@workerman.net>
 * @copyright walkor<walkor@workerman.net>
 * @link      http://www.workerman.net/
 * @license   http://www.opensource.org/licenses/mit-license.php MIT License
 */
namespace GatewayWorker\Lib;

use Exception;
use GatewayWorker\Protocols\GatewayProtocol;
use Workerman\Connection\TcpConnection;

/**
 * 数据发送相关
 */
class Gateway
{

private $redis;

    public $checkUserReadable = false;

    public static function setChatRecord($from, $to, $message) {
        $data = array('from' => $from, 'to' => $to, 'message' => $message, 'sent' => time());
        $value = json_encode($data);
        //生成json字符串
        $keyName = 'rec:' . self::getRecKeyName($from, $to);
            $redis = new Redis(); 
            $redis->connect('127.0.0.1', 6379);   
        $res =  $redis -> lPush($keyName, $value);
        if (!$this -> checkUserReadable) {//消息接受者无法立刻查看时，将消息设置为未读
            return $redis -> hIncrBy('unread_' . $to, $from, 1);
        }
        return $res;

    }
       private static function getRecKeyName($from, $to) 
            { if ($from > $to){return  $to . '_' . $from;

                          }else{ return  $from . '_' . $to;}
            }
    /**
     * gateway 实例
     */

报错信息

Fatal error: Class 'GatewayWorker\Lib\Redis' not found in /pi/components/com_work/GatewayWorker/Lib/Gateway.php on line 49
WORKER EXIT UNEXPECTED E_ERROR Class 'GatewayWorker\Lib\Redis' not found in /pi/components/com_work/GatewayWorker/Lib/Gateway.php on line 49
worker exit with status 65280

49行就是$redis = new Redis(); 是不是不能直接使用redis.