How to get response stream after uploading a file using Backgrounduploader

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C#

Metro-design

I am working on a metro app. I used background uploader to upload file but my question is how I get response value after uploading it. I coded like this:

BackgroundUploader uploader = new BackgroundUploader();
           uploader.SetRequestHeader("Content-Disposition", "form-data");
           uploader.SetRequestHeader("name", "userfile");
           uploader.SetRequestHeader("filename", App.ViewModel.DeviceId + ".png");
           uploader.SetRequestHeader("Content-Type", "multipart/form-data");

           UploadOperation upload = uploader.CreateUpload(uri, file);
           await upload.StartAsync()