tcp 连接双向拷贝 无效的tcp连接不能被识别关闭

func (client *ForwardInfo) StartOneForward(tcpConn net.Conn) {
    defer tcpConn.Close()
    //连接目标地址1
    conn1, err := net.DialTimeout("tcp", client.Dest1, 30*time.Second)
    //连接目标地址2
    conn2, err := net.DialTimeout("tcp", client.Dest2, 30*time.Second)
    if err != nil {
        public.ForwardLog.Error("转发出现异常 Forward to Dest Addr err:", err.Error())
        return
    }
    defer func() {
        conn1.Close()
        conn2.Close()
    }()
    public.ForwardLog.Info("新用户 ", tcpConn.RemoteAddr().String(), "开始TCP转发 --> ", client.Dest1, ",", client.Dest2)
    conns := ClientConn{
        Uuid:      uuid.New(),
        SrcConn:   tcpConn,
        Dest1Conn: conn1,
        Dest2Conn: conn2,
    }
    client.ClientInfoMap.Set(conns.Uuid, &conns)
    go func() {
        multiReader := io.MultiReader(conns.Dest1Conn, conns.Dest2Conn)
        _, err := io.Copy(conns.SrcConn, multiReader)
        if err != nil {
            conns.StopForward(client) //关闭连接
        }
    }()

    writer := io.MultiWriter(conns.Dest1Conn, conns.Dest2Conn)
    _, err = io.Copy(writer, conns.SrcConn)
    if err != nil {
        conns.StopForward(client) //关闭连接
    }
}

我正在用io.cpoy对进入的tcp连接复制到2条新连接上，发现有些tcp连接被关闭了，可是无法调用StopForward方法进行tcp关闭