NegotiateExtensions.cs

public static class NegotiateExtensions
{
    public static Negotiator WithCrazyModel(this Negotiator negotiator, object model)
    {
        return negotiator
            .WithMediaRangeModel(MediaRange.FromString("application/foo"), new FooWrapper(model))
            .WithMediaRangeModel(MediaRange.FromString("application/bar"), new BarWrapper(model));
    }
}