The Ledger API provides direct access to ledgers and thus enables you to use BookKeeper however you’d like.
However, in most of use cases, if you want a log stream-like abstraction, it requires you to manage things like tracking list of ledgers,
managing rolling ledgers and data retention on your own. In such cases, you are recommended to use DistributedLog API,
with semantics resembling continous log streams from the standpoint of applications.