public override string SendRequest(string url, KeyValuePair<string, string>[] parameters, WebProxy proxy)
{
var buffer = parameters.ToPostBuffer();
var request = (HttpWebRequest) WebRequest.Create(url);
request.ContentType = "application/x-www-form-urlencoded";
request.Method = "POST";
request.Proxy = proxy ?? WebRequest.DefaultWebProxy;
request.ContentLength = buffer.Length;
var postStream = request.GetRequestStream();
postStream.Write(buffer, 0, buffer.Length);
postStream.Close();
return GetResponse(request);
}