anchor.diff:  let rec processMessages (reader:StreamReader) (writer:StreamWriter) = async {
       let line = reader.ReadLine()
   
  -    match reader.EndOfStream with
  -    | false ->
  +    if line <> null then
           if line.Length > 0 then
               if line.StartsWith "PING " then
                   writer.WriteLine ("PONG " + line.Substring("PING ".Length))
  
positive.code:         Async.Start (processMessages reader writer)
  
          writer.NewLine <- "\r\n"
          // Replace the empty strings with your user credentials (username, oauth)
          writer |> login username password
          writer |> processInput (Console.ReadLine())
      | _ ->
  
negative.code:                 processLine line |> ignore
  
          return! processMessages reader writer
      else
          ()
  }
  
  