Notify before a scheduled backup, giving the option to cancel and maybe to delay

[t-m-w]

Before performing a scheduled backup, notify that it is about to occur. Offer the ability to cancel that particular scheduled run, and possibly to delay it.

I'm not sure how much time is appropriate for a warning - I could see as low as 30 seconds, as high as 2 minutes, maybe?

Would be helpful if the notification could "count down" but having one at all would be nice.