@AfterClass
  public static void tearDownAfterClass() throws Exception {
    Closeables.close(ASYNC_CONN, true);
    TEST_UTIL.shutdownMiniCluster();
  }
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