[keycloak-user] Authentication SPI implementation for RADIUS

I'm not finding an implementation of Keycloak Authentication SPI for RADIUS. Am I crazy just for looking? I mean, is the absence of such a warning for folks? Or has it simply not been tried? I don't find much of a demand for one either. So maybe that is the case, I hope. I think we'll have to write one to satisfy internal customer request. Is there anyone willing to claim they attempted such? I'd like to hear from you regarding approach and success. Thanks, John