Cannot get the download to work in CSV formatter sample

[mishrsud]

I've downloaded the code from the repository but face the following issues after building and running using IIS Express (VS 2012):
I get an exception -
Method not found: 'Void System.Net.Http.Headers.HttpHeaders.AddWithoutValidation(System.String, System.Collections.Generic.IEnumerable`1<System.String>)'. Object Explorer confirms that there is no such method in System.Net.Http.Headers.HttpHeaders - what version of System.Net assembly are you using? can I download that version from somewhere?

I've followed the code from your blog and created a CsvMediaTypeFormatter in a standalone project, but I needed to add streamWriter.Flush() call to get data in the downloaded file. Removing the call to flush causes the CSV file to not have any data