@Override
    public String getWALFile() {
      return ZKSplitLog.getFileName(taskNode);
    }
When ZK-based implementation wants to complete the task, it needs to know task znode and
current znode cversion (needed for subsequent update operation).
hbase-server/src/main/java/org/apache/hadoop/hbase/coordination/ZkSplitLogWorkerCoordination.java