Reading SyndicationFeed in background

Uri uri = new Uri( feedUri);            SyndicationClient client = new SyndicationClient();            SyndicationFeed currentFeed = await client.RetrieveFeedAsync(uri);            XmlDocument toastXml = ToastNotificationManager.GetTemplateContent(ToastTemplateType.ToastImageAndText03);            XmlNodeList toastTextElement = toastXml.GetElementsByTagName("text");            toastTextElement[0].AppendChild(toastXml.CreateTextNode("Working"));            ToastNotification toast = new ToastNotification(toastXml);            ToastNotificationManager.CreateToastNotifier().Show(toast);

nothing is being executed after RetrieveFeedAsync.