What does this stasis app message mean

I see the following message appearing regularly on my PBX console:

-- Inactive Stasis app 'XXX' missed message

(I obfuscated XXX). XXX is an app I am developing, but it’s stopped right now. Why does the above message occur?

This is an ARI thing. You have opened a WebSocket connection to listen for events relating to a particular ARI “application” name, and now that “application” name stays in existence for the rest of the life of the current Asterisk process, with no way to get rid of it.

Can I unregister my app XXX on app shutdown? So that Asterisk no longer tries to send it messages?

No. There is currently no support for doing such a thing.