Module persist state across Access-Challenge

Is there any mechanism to allow a module to persist some state between an Access-Challenge with a State attribute and then the subsequent new Access-Request? It seems like an obvious use of State would be to index into some persisted state but I don't see anything readily available. As far as I can tell pushing VALUE_PAIRS on the REQUEST seem to only be persisted across invocations of the various module methods (auth, authz, etc.) r