Adding alternative responses to the NancyContext.Items dictionary

ContentNegotiationExtensions.cs

 public static void AddAlternateResponses<T>(this NancyContext context, T resource,
            HttpStatusCode statusCode = HttpStatusCode.OK, string location = null)
        {
            var xmlResponse = new XmlResponse<T>(resource, "application/xml", new DefaultXmlSerializer())
                {
                    StatusCode = statusCode
                };
            var jsonResponse = new JsonResponse(new { resource }, new DefaultJsonSerializer())
            {
                StatusCode = statusCode
            };

            if (location != null)
            {
                xmlResponse = (XmlResponse<T>) xmlResponse.WithHeader("Location", location);
                jsonResponse = (JsonResponse) jsonResponse.WithHeader("Location", location);
            }
            context.Items.Add("Content-Negotiation", new List<Response> { xmlResponse, jsonResponse });
        }