async void updateGuiOn1secTimerTick()
        {
            var tnow = DateTime.Now;
            var idle = ((tnow - App.StartedAt) + TimeSpan.FromSeconds(App.ScrSvrTimeoutSec));
            var left = App.StartedAt.AddMinutes(AppSettings.Instance.Min2Sleep) - tnow;

            tbOutOffL.Text = (idle.TotalMinutes < 60 ? $"{idle:m\\:ss}" : $"{idle:h\\:mm} ");

            if (AppSettings.Instance.AutoSleep)
            {
                tbOutOffR.Text   = (left.TotalMinutes < 60 ? $"{left:m\\:ss}" : $"{left:h\\:mm} ");
                pbOutOff.Maximum = (idle + left).TotalMinutes;
                pbOutOff.Value   = idle.TotalMinutes;
                pbOutOff.Opacity = pbOutOff.Maximum > 0 ? pbOutOff.Value / pbOutOff.Maximum : 0;
            }
            else
            {
                tbOutOffR.Text = "";
            }

            if (!_isTalking && idle.TotalSeconds % 60 <= (_timerePeriodSec + _gracePeriodSec))
            {
                try
                {
                    _isTalking = true;
                    _timer.Stop();

                    g1.Background = _red;

                    if (AppSettings.Instance.IsSayMinOn || AppSettings.Instance.IsChimesOn || AppSettings.Instance.IsRepeatOn)
                    {
                        await ChimerAlt.WakeAudio(); // wake up monitor's audio.

                        if (AppSettings.Instance.IsSayMinOn)
                        {
                            await App.SpeakAsync($"{idle.Minutes}");
                        }
                        if (AppSettings.Instance.IsChimesOn)
                        {
                            await ChimerAlt.Chime(idle.Minutes);                      //nogo: .ConfigureAwait(false);
                        }
                        if (AppSettings.Instance.IsRepeatOn)
                        {
                            App.SpeakFaF($"{idle.Minutes} minutes, that is.");
                        }
                        g1.Background = _rng;
                    }

                    await Task.Delay((int)(_gracePeriodSec * 1000)); // lest repeat the same on the next tick (2020-12-02)

                    g1.Background = _trn;
                }
                catch (Exception ex) { ex.Log(); }
                finally
                {
                    _isTalking = false;
                    _timer.Start();
                }
            }
        }
 async void onFreqWalk(object s, RoutedEventArgs e) => await ChimerAlt.FreqWalkUpDn();