调用第三方系统接口，请求被中止: 未能创建 SSL/TLS安全通道

        当通过HttpWebRequest调用第三方系统接口时，如果是https，会出现“请求被中止: 未能创建 SSL/TLS 安全通道”。

        HttpWebRequest对象需要针对https做对应的处理，部分示例代码如下：

            //创建httpWebRequest对象
            HttpWebRequest httpRequest = null;
            if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
            {
                ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;
                ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3
                                   | SecurityProtocolType.Tls
                                   | (SecurityProtocolType)0x300 //Tls11
                                   | (SecurityProtocolType)0xC00; //Tls12

                httpRequest = WebRequest.Create(url) as HttpWebRequest;
                httpRequest.ProtocolVersion = HttpVersion.Version10;
            }
            else
            {
                httpRequest = WebRequest.Create(url) as HttpWebRequest;
            }