private void finish() {
      synchronized (controller.dataAvailable) {
        shouldStop = true;
        controller.dataAvailable.notifyAll();
      }
    }
Set status message in {@link MonitoredTask} instance that is set in this OutputSink
@param msg message to update the status with
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/OutputSink.java