当系统环境具有多IP时使用httpwebrequest指定请求 源IP的方法

    var servicePointUserReader = ServicePointManager.FindServicePoint(new Uri("https://ipv4.gdt.qq.com/get_client_ip"));
    servicePointUserReader.BindIPEndPointDelegate = (sp, remote, retryCount) => new IPEndPoint(IPAddress.Parse("192.168.1.45"), 0);