七牛跨服务器上传文件带参数

 HttpPostedFileBase file = Request.Files["file"];
            //System.IO.Stream s = file.InputStream;
            byte[] buffer = new byte[1024]; 
            //int bytesRead = 0;
            //while ((bytesRead = file.InputStream.Read(buffer, 0, buffer.Length)) != 0)
            //{

            //}
            buffer=StreamToBytes(file.InputStream);

            using (var httpClient = new HttpClient())
            {
                httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("image/jpeg"));//设定要响应的数据格式  
               using (var content = new MultipartFormDataContent())//表明是通过multipart/form-data的方式上传数据  
                {
                 //   content.Add(new ByteArrayContent(buffer, 0, buffer.Count()), "file", "aaasf.jpg");

                    var policy = new Qiniu.RS.PutPolicy("file", 3600);
                 //   content.Add(new StringContent("0"), "detectMime");     
                    content.Add(new StringContent(Guid.NewGuid().ToString()), "key");
                    content.Add(new StringContent("file"), "bucket");
                    var imageContent = new ByteArrayContent(buffer, 0, buffer.Count());
                    imageContent.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg");
                    content.Add(imageContent, "file", file.FileName);
                    content.Add(new StringContent(policy.Token()), "token");
                //  content.Add(new StringContent("image/jpeg"), "Accept");  
                    var result = httpClient.PostAsync("http://up.qiniu.com", content).Result.Content.ReadAsStringAsync().Result;
                      
               }                           
            }   

 public byte[] StreamToBytes(Stream stream)
        {
            byte[] bytes = new byte[stream.Length];
            stream.Read(bytes, 0, bytes.Length);
            // 设置当前流的位置为流的开始
            stream.Seek(0, SeekOrigin.Begin);
            return bytes;
        }