@Override
      public boolean evaluate() throws Exception {
        try {
          SlowMeCopro.cdl.set(new CountDownLatch(1));
          Get g = new Get(row);
          g.setConsistency(Consistency.TIMELINE);
          Result r = table2.get(g);
          Assert.assertTrue(r.isStale());
          return !r.isEmpty();
        } finally {
          SlowMeCopro.cdl.get().countDown();
          SlowMeCopro.sleepTime.set(0);
        }
      }
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