anchor.diff:      async { 
           try
               use client = createWebClient(url,auth)
  -            return! client.AsyncDownloadString(Uri(url))
  +            let s = client.DownloadStringTaskAsync(Uri(url)) |> Async.AwaitTask
  +            return! s
           with
           | exn -> 
               failwithf "Could not retrieve data from %s%s Message: %s" url Environment.NewLine exn.Message
  
positive.code:     async { 
          try 
              use client = createWebClient(url,auth)
              let! raw = client.AsyncDownloadString(Uri(url))
              return Some raw
          with _ -> return None
      }
  
negative.code:             client.Headers.Add(HttpRequestHeader.AcceptCharset, "UTF-8")
              client.Headers.Add("DataServiceVersion", "1.0;NetFx")
              client.Headers.Add("MaxDataServiceVersion", "2.0;NetFx")
              
              let s = client.DownloadStringTaskAsync(Uri(url)) |> Async.AwaitTask
              return! s
          with
          | exn -> 
              failwithf "Could not retrieve data from %s%s Message: %s" url Environment.NewLine exn.Message
  