(PECL zookeeper >= 0.1.0)
Zookeeper::setWatcher — Set a watcher function
watcher_cbA watch will be set at the server to notify the client if the node changes.
Retorna TRUE em caso de sucesso ou FALSE em caso de falha.
This method emits PHP error/warning when parameters count or types are wrong or fail to set watcher.
Since version 0.3.0, this method emits ZookeeperException and it's derivatives.