PostRaw

private string PostRaw(string url, string data)
{
    var request = (HttpWebRequest)WebRequest.Create(url);
    request.ContentType = "application/json";
    request.Method = "POST";
    using (var requestWriter = new StreamWriter(request.GetRequestStream()))
    {
        requestWriter.Write(data);
    }

    var response = (HttpWebResponse)request.GetResponse();
    if (response == null)
        throw new InvalidOperationException("GetResponse returns null");

    using (var sr = new StreamReader(response.GetResponseStream()))
    {
        return sr.ReadToEnd();
    }
}