private void exec(TableName tableName, int rlen, int vlen, int rows) throws IOException {
    try (Connection conn = ConnectionFactory.createConnection(getConf())) {
      try (Admin admin = conn.getAdmin()) {
        if (!admin.tableExists(tableName)) {
          createTable(admin, tableName);
        }
      }
      try (Table table = conn.getTable(tableName)) {
        checkLag(table, rlen, vlen, rows);
      }
    }
  }
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