If I understand correctly, this trait is being used in order to have the ability to switch out the locking mechanism to zoopkeeper?

What do you think of also having a local version that just uses `AsyncMutex`? See [KafkaStore](https://github.com/twitter/storehaus/blob/develop/storehaus-kafka/src/main/scala/com/twitter/storehaus/kafka/KafkaStore.scala#L37) for example usage.