If you can't show me a spinner or other indicator that this is an ongoing operation (which I find preferable), and you think I will have moved away from the controls for this, then put it in a central location that I will see even if I am still on your control, not in a little box on the other side of the screen.

These toast notifications just are a bad solution. I often miss them, because I'm, you know, doing work, not scanning my monitors for notifications I mostly don't care about. (Redundancy is not harmless. Redundancy also trains me that your messaging is mostly noise.)