@Override
        public void start(Path configFilePath) {
            phaser.awaitAdvance(phaser.arriveAndDeregister());
            serverPeer.start(configFilePath);
        }
Tests dynamic reconfiguration of zookeeper cluster.

@author hmusum
zookeeper-server/zookeeper-server-common/src/test/java/com/yahoo/vespa/zookeeper/ReconfigurerTest.java