ServiceStack.HttpUtils.UploadFile C# (CSharp) Method

        public static void UploadFile(this WebRequest webRequest, Stream fileStream, string fileName, string mimeType,
            string accept = null, Action<HttpWebRequest> requestFilter = null, string method = "POST")
        {
            var httpReq = (HttpWebRequest)webRequest;
            httpReq.UserAgent = Env.ServerUserAgent;
            httpReq.Method = method;
            httpReq.AllowAutoRedirect = false;
            httpReq.KeepAlive = false;

            if (accept != null)
                httpReq.Accept = accept;

            if (requestFilter != null)
                requestFilter(httpReq);

            var boundary = "----------------------------" + DateTime.UtcNow.Ticks.ToString("x");

            httpReq.ContentType = "multipart/form-data; boundary=" + boundary;

            var boundarybytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");

            var headerTemplate = "\r\n--" + boundary +
                                 "\r\nContent-Disposition: form-data; name=\"file\"; filename=\"{0}\"\r\nContent-Type: {1}\r\n\r\n";

            var header = string.Format(headerTemplate, fileName, mimeType);

            var headerbytes = Encoding.ASCII.GetBytes(header);

            httpReq.ContentLength = fileStream.Length + headerbytes.Length + boundarybytes.Length;

            if (ResultsFilter != null)
            {
                ResultsFilter.UploadStream(httpReq, fileStream, fileName);
                return;
            }

            using (Stream outputStream = httpReq.GetRequestStream())
            {
                outputStream.Write(headerbytes, 0, headerbytes.Length);

                byte[] buffer = new byte[4096];
                int byteCount;

                while ((byteCount = fileStream.Read(buffer, 0, 4096)) > 0)
                {
                    outputStream.Write(buffer, 0, byteCount);
                }

                outputStream.Write(boundarybytes, 0, boundarybytes.Length);

                outputStream.Close();
            }
        }