```
               var uri = URL_BASE + myuri
                          string.Format("providers/{0}/items?feed={1}&id={2}&type=cf", provider, feed, zipFileNoPath);
                var webClient = new WebClient();
                webClient.Credentials = new NetworkCredential(email, password);
                webClient.Headers.Add("Accept", "*/*");
                webClient.Headers.Add("Content-Type", "application/octet-stream");
                webClient.UploadFileAsync(new Uri(uri), "POST", zipFile);

```

for the above code, when I watch in from fiddler, I saw two "Content-Type" in header
One is Content-Type: multipart/form-data; boundary=---------------------8cf27396e080e0a, 
The other is Content-Type: application/octet-stream
why whould this be? whichone takes effect then, thanks