C# 调用微信红包接口类中第三个参数strEncoding是什么意思

C# 调用微信红包接口类中第三个参数strEncoding是什么意思，如何取得。请大神指点。
public string OpenReadWithHttps(string URL, string strPostdata, string strEncoding)
{
try
{
Encoding encoding = Encoding.UTF8;

        string cert = @"C:\zhengshu\apiclient_cert.p12";
        string password = "xxxxxx";//这里是填写的是 微信支付商户号

        ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
        X509Certificate cer = new X509Certificate(cert, password);
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
        request.ClientCertificates.Add(cer);


        request.Method = "post";

        request.Accept = "text/html, application/xhtml+xml, */*";

        request.ContentType = "application/x-www-form-urlencoded";


        byte[] buffer = encoding.GetBytes(strPostdata);

        request.ContentLength = buffer.Length;

        request.GetRequestStream().Write(buffer, 0, buffer.Length);

        HttpWebResponse response = (HttpWebResponse)request.GetResponse();

        using (StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.GetEncoding(strEncoding)))
        {
            return reader.ReadToEnd();
        }
    }
    catch (Exception e)
    {

        return "";
    }

}

using (StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.GetEncoding(**strEncoding**)))

就是用上面编码来读取返回的2进制数据流，如utf-8，gb2312。微信一般都是返回utf-8的，直接传递utf-8就行了。如果你请求的是其他url地址，返回的是gb2312编码的你就需要传递gb2312编码

strEncoding就是编码的名称，怎么确定得看URL这个地址返回什么编码的数据，要不编码不对会乱码

https://msdn.microsoft.com/zh-cn/library/t9a3kf7c.aspx

2楼大神的意思是：第三个参数 strEncoding我直接带入“utf-8” 就可以了是吗？