public ActionResult GetPageData(int page = 1, int size = 10, string search = "")
        {
            List <Broadcast> list;
            int total;

            if (string.IsNullOrEmpty(search))
            {
                list = BroadcastService.LoadPageEntitiesFromL2CacheNoTracking(page, size, out total, b => true, b => b.UpdateTime, false).ToList();
            }
            else
            {
                list = BroadcastService.LoadPageEntitiesFromL2CacheNoTracking(page, size, out total, b => b.Email.Contains(search), b => b.UpdateTime, false).ToList();
            }
            var pageCount = Math.Ceiling(total * 1.0 / size).ToInt32();

            return(Ok(new PageDataModel(list, pageCount, total)));
        }