public async Task <FileResult> DownloadFile(int id)
        {
            var file = await _postAppService.GetAttachment(id);

            var realUrl = file.ContentUrl;

            if (!file.StoredInCdn)
            {
                realUrl = Server.MapPath(file.ContentUrl);
            }
            try
            {
                var fileBytes = System.IO.File.ReadAllBytes(realUrl);
                return(File(fileBytes, file.FileName));
            }
            catch (Exception ex)
            {
                throw new UserFriendlyException(ex.Message);
            }
        }