@AfterClass
  public static void afterClass() throws Exception {
    if (HTU2 != null) HTU2.shutdownMiniCluster();
    HTU.shutdownMiniCluster();
  }
This copro is used to slow down the primary meta region scan a bit
hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestReplicaWithCluster.java