Once #1000 is closed (which is not a priority, but will be wonderful), let's also let Bob in on the action by creating ways for Alice to share the checksum of a canonical fleet state.

Since we require Bob to do complete node discovery without a blockchain connection - which causes us to have to address some fairly complex asychrony issues like #2150, let's reduce his overall burden by allowing him to rest once he has a good enough fleet state to retrieve.