/// <summary>
        /// Read the app configuration JSON and perform additional initialization.
        /// MUST NOT throw.
        /// </summary>
        /// <returns></returns>
        static async Task LoadAppConfiguration()
        {
            try {
                var sf = await Package.Current.InstalledLocation.GetFileAsync(@"Assets\AppConfiguration.json");

                var jsonText = await Windows.Storage.FileIO.ReadTextAsync(sf);

                var json = JsonObject.Parse(jsonText);
                LogTools.FromContainer(json.GetNamedObject("TraceSwitches"), (ijv) => {
                    var did = Enum.TryParse(ijv.GetString(), out LogTools.Level level);
                    return(did ? level : LogTools.Level.Info);
                });
            } catch (Exception ex) {
                System.Diagnostics.Debug.WriteLineIf(true, $"LoadAppConfiguration.unhandled: {ex.Message}");
            }
        }