How to sync a Doc with leveldb like other providers

WebsocketProvider has:

new WebsocketProvider(url, docName, ydoc)

IndexedDBProvider has:

new IndexeddbPersistence(docName, ydoc)

What’s the equivalent with y-leveldb?

// this would be nice...
new LeveldbPersistence(storageDir, docName, ydoc)

I’m confused why y-leveldb has such a different API than the other providers.