public static String QueryStringForTR(Request trParams, Request req, String postURL, BraintreeService service)
{
String trData = TrUtil.BuildTrData(trParams, "http://example.com", service);
String postData = "tr_data=" + HttpUtility.UrlEncode(trData, Encoding.UTF8) + "&";
postData += req.ToQueryString();
var request = WebRequest.Create(postURL) as HttpWebRequest;
request.Method = "POST";
request.KeepAlive = false;
byte[] buffer = Encoding.UTF8.GetBytes(postData);
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = buffer.Length;
Stream requestStream = request.GetRequestStream();
requestStream.Write(buffer, 0, buffer.Length);
requestStream.Close();
var response = request.GetResponse() as HttpWebResponse;
String query = response.ResponseUri.Query;
response.Close();
return query;
}