NewZooKeeperBackend constructs a ZooKeeper backend using the given API client and the prefix in the KV store.

ZKNodeFilePrefix is prefixed to any "files" in ZooKeeper, so that they do not collide with directory entries.

ZooKeeperBackend is a physical backend that stores data at specific prefix within ZooKeeper.

ZooKeeperHALock is a ZooKeeper Lock implementation for the HABackend.