gistfile1.cs

 public class PlainTextFormatter : MediaTypeFormatter
    {
        public PlainTextFormatter()
        {
            SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/plain"));
        }

        protected override System.Threading.Tasks.Task<object> OnReadFromStreamAsync(Type type, System.IO.Stream stream, HttpContentHeaders contentHeaders, FormatterContext formatterContext)
        {
            return new Task<object>(() =>
                                        {
                                            return new StreamReader(stream).ReadToEnd();
                                        });
        }

        protected override Task OnWriteToStreamAsync(Type type, object value, Stream stream, HttpContentHeaders contentHeaders, FormatterContext formatterContext, System.Net.TransportContext transportContext)
        {
            return  new Task(() =>
                                 {
                                     var writer = new StreamWriter(stream);
                                     writer.Write(value.ToString());
                                 });
        }
        protected override bool CanReadType(Type type)
        {
            return true;
        }

        protected override bool CanWriteType(Type type)
        {
            return true;
        }
    }