CAEP provides this to some extent https://openid.net/wg/sse/ https://openid.net/wg/sse/ - but now you're asking for a whole bunch of systems to be able to talk

CAEP provides this to some extent https://openid.net/wg/sse/ https://openid.net/wg/sse/ - but now you're asking for a whole bunch of systems to be able to talk about you in back channels which other people will find fault with.