Notify Action if the context is not canceled within grace period.

func yourHandler() {
    // the "recording audio" notification will be sent if we're not able to get the voice generated within 2 seconds.
    cancelNotify := b.sendNotifyAction(ctx, chat, notifyGraceTime)
    voice, cl, genErr := gen.ForUser(ctx, user, text)
    cancelNotify()

// ...
}

// sendNotifyAction sends the "recording" notification if the gracePeriod expires
// before cancelFn function is called.
func (b *Bot) sendNotifyAction(ctx context.Context, r tb.Recipient, gracePeriod time.Duration) (cancelFn func()) {
    timeoutCtx, cancel := context.WithTimeout(ctx, 5*time.Minute) // this should never happen, just in case
    go func() {
        region := trace.StartRegion(timeoutCtx, "sendNotifyAction")
        defer region.End()

        select {
        case <-time.After(gracePeriod):
            trace.Logf(ctx, "notify", "sending notify action")
            if err := b.bot.Notify(r, tb.RecordingAudio); err != nil {
                dlog.Printf("%s: notification error: %s", caller(0), err)
            }
        case <-timeoutCtx.Done():
            trace.Logf(timeoutCtx, "notify", timeoutCtx.Err().Error())
            return
        }
    }()
    return cancel
}