Currently, acquire a topic needs to load both persistence info and subscriptions info at the same time. only after that, the topic acquisition could succeed. but it seems that, for a sub/closesub/unsub request, we just need subscription info. for a pub request, we just need persistence info. especially, for a subscriber requests, we don't need to create a new ledger if there is no messages. we could delay provisioning ledger when messages arrive. otherwise, it introduced unnecessary metadata creation.
for some applications, lazily loading might be necessary. for some applications, it might be not. it should be configurable.