[juliangruber]

- there's no locking unless you introduce it

- snapshots are create implicitly when using a reading stream. there isn't yet an api that exposes them directly.

- if you need transactions, write a node module that implements them

- create{Key,Value,Read}Stream uses snapshots internally

- createWriteStream is aggregating some of its values into batches for performance reasons, but not locking

- levelup/multilevel streams behave the way node.js streams should behave