public async Task InvokeAsync(
            HttpContext context,
            IContentStorage contentStore,
            JsonService jsonService)
        {
            RestContentItem input = await jsonService.Deserialize <RestContentItem>(context.Request.Body);

            ContentItem model = input.ToModel();

            await contentStore.UpdateAsync(model);

            ResourceCreated result = new ResourceCreated()
            {
                Id = input.Id
            };

            string json = jsonService.Serialize(result);

            await context.Response.WriteAsync(json);
        }