public static void main(String[] args) throws Exception {
    int res =
      ToolRunner.run(HBaseConfiguration.create(), new RegionReplicationLagEvaluation(), args);
    System.exit(res);
  }
A tool to evaluating the lag between primary replica and secondary replica.
<p/>
It simply adds a row to the primary replica, and then check how long before we can read it from
the secondary replica.
hbase-server/src/test/java/org/apache/hadoop/hbase/RegionReplicationLagEvaluation.java