Unity - A计划（永久有效期） 扫二维码继续学习 二维码时效为半小时

using PENet;
using PEProtocol;
using System.Collections.Generic;

class NetSvc
{
    private static NetSvc instance = null;
    public static NetSvc Instance
    {
        get
        {
            if (instance == null)
            {
                instance = new NetSvc();
            }
            return instance;
        }
    }

    public static readonly string obj = "lock";//这个是干什么用的？
    /// <summary>
    /// 接受消息队列
    /// </summary>
    private Queue<GameMsg> msgPackQue = new Queue<GameMsg>();

    public void Init()
    {
        PESocket<ServerSession, GameMsg> server = new PESocket<ServerSession, GameMsg>();
        server.StartAsServer(SrvCfg.srvIP, SrvCfg.srvPort);

        PECommon.Log("NetSvc Init Done.");
    }

    public void AddMsgQue(GameMsg msg)
    {
        lock (obj)
        {
            msgPackQue.Enqueue(msg);
        }
    }
}

线程锁我知道，为什么不是锁队列msgPackQue，锁一个只读字符串是什么操作？