Everything I can find on toast notifications is about how to send them or fix problems with sending them.
I have a full-screen desktop application where I want to STOP toast from popping up while it runs.
So far the only way I've found to do this is manually -- group policy, user going to Windows settings.
The MS docs on toast notifications list a property to tell you if toast is blocked, but it is read-only so you can't set it with code.