We were working on BOOKKEEPER-249 for a new GC algorithm using ZooKeeper
multi-update feature. But it seems that there is no async interface for
multi request in ZooKeeper client. As my knowledge about ZooKeeper, the
difference between sync interface and async interface is using
cnxn.submitRequest for sync interface while using cnxn.queuePacket for
async interface. It would be quite easy to have an async interface for
multi. Is there any consideration why not introducing an async api when
developing multi feature?