public static ResponseDescription CreateResponseDescription(this HttpActionDescriptor actionDescriptor)
        {
            Contract.Requires(actionDescriptor != null);

            var responseTypeAttribute = actionDescriptor.GetCustomAttributes <ResponseTypeAttribute>();
            var responseType          = responseTypeAttribute.Select(attribute => attribute.ResponseType).FirstOrDefault();

            return(new ResponseDescription
            {
                DeclaredType = actionDescriptor.ReturnType,
                ResponseType = responseType,
                Documentation = actionDescriptor.GetApiResponseDocumentation()
            });
        }