Refactor fetchEntryInfosByID so that it accepts a set of ids. Something similar could be done for fetchKnownUserInfos but it is used in a lot of places so it would be expensive.
Also, replace ids arrays with sets in checkState - that makes sense on its own, but also is beneficial because it makes interfaces of specs more unified.
https://linear.app/comm/issue/ENG-4654/unify-interfaces-in-session-utils