private Hbck getHbck() throws Exception {
    if (async) {
      return ASYNC_CONN.getHbck().get();
    } else {
      return TEST_UTIL.getHbck();
    }
  }
Class to test HBaseHbck. Spins up the minicluster once at test start and then takes it down
afterward. Add any testing of HBaseHbck functionality here.
hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestHbck.java