Understand if client needs to know sequence number of topics

[willscott]

Presumably it needs to keep track of where it is in a topic handle, but how does that bootstrap initially? in practice, the shared secret with the topic password should probably also indicate the 'current' sequence number, and the client will 'catch up' and then keep track of where it is from there.

That requires a stateful client though, so there needs to be an interface for the topic to be serialized and restored with both the current sequence number and the seed.