aspnet web api json MediaTypeFormatter using Servicestack.Text

ServiceStackTextFormatter.cs

public class ServiceStackTextFormatter : MediaTypeFormatter
{
	public ServiceStackTextFormatter()
	{
		// Fill out the mediatype and encoding we support
		SupportedMediaTypes.Add(new MediaTypeHeaderValue("application/json"));
		Encoding = new UTF8Encoding(false, true);
	}

	protected override Task<object> OnReadFromStreamAsync(Type type, Stream stream, HttpContentHeaders contentHeaders, FormatterContext formatterContext)
	{
		// Create task reading the content
		return Task.Factory.StartNew(() =>
		    {
				return JsonSerializer.DeserializeFromStream(type, stream);
		    });
	}

	protected override Task OnWriteToStreamAsync(Type type, object value, Stream stream, HttpContentHeaders contentHeaders, FormatterContext formatterContext, TransportContext transportContext)
	{
		// Create task writing the serialized content
		return Task.Factory.StartNew(() =>
			{
				JsonSerializer.SerializeToStream(value, stream);
			});
	}

	protected override bool CanReadType(Type type)
	{
		if (type == typeof(IKeyValueModel))
			return false;

		return true;
	}

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