I've got a best-practices sort of question here. I'm developing a service that subscribes to streaming notifications to respond to incoming mail. It's going to be pretty stable so streaming should work most of the time, but I have to plan for the inevitable failure (server crashes, maintenance restarts, etc.).
My thought is to sync the folder when the service starts or connection is restored after a loss to make sure I didn't miss anything while the connection was unavailable. The problem is how do I avoid getting events for which I've already received notification? It would be easy if the streaming notifications were coupled with watermarks or syncstates I could use in a standard folder sync request, but I don't see that they are.
Fairly new to exchange development, so maybe I'm missing something.