public static class PrefetchHelpers
    {
        public static MvcHtmlString Prefetcher(this HtmlHelper html)
        {
            var session = html.ViewContext.RequestContext.HttpContext.Session;
            if (session == null)
                return MvcHtmlString.Create("<iframe style=\"display: none;\" src=\"/Cms/Prefetch\"></iframe>");

            if(session["NOT_FIRST_PAGE"] == null || !(bool) session["NOT_FIRST_PAGE"])
            {
                session["NOT_FIRST_PAGE"] = true;
                return MvcHtmlString.Create("<iframe style=\"display: none;\" src=\"/Cms/Prefetch\"></iframe>");
            }

            return MvcHtmlString.Empty;
        }
    }