For my use case, the volume of messages was not an issue. This isn't a huge app that is pushing out tons of notifications. We're talking 10's or 100's a day, maybe.
In fact, it didn't matter at all once the initial notification was visible whether follow-on notifications were displayed. Possibly the fact that I was locally dropping the notifications (because the user didn't need them), the system counted those as "notification that weren't interacted with, so I'm going to slow you down at the server."?
I have no idea, and no way to find out, since FCM is pretty opaque at this point.
In fact, it didn't matter at all once the initial notification was visible whether follow-on notifications were displayed. Possibly the fact that I was locally dropping the notifications (because the user didn't need them), the system counted those as "notification that weren't interacted with, so I'm going to slow you down at the server."?
I have no idea, and no way to find out, since FCM is pretty opaque at this point.