@AfterClass
  public static void tearDownAfterClass() throws Exception {
    if (EVENT_LOOP_GROUP != null) {
      EVENT_LOOP_GROUP.shutdownGracefully().get();
    }
    if (KDC != null) {
      KDC.stop();
    }
    shutdownMiniDFSCluster();
  }
Sets up {@link MiniKdc} for testing security. Uses {@link HBaseKerberosUtils} to set the given
keytab file as {@link HBaseKerberosUtils#KRB_KEYTAB_FILE}.
hbase-asyncfs/src/test/java/org/apache/hadoop/hbase/io/asyncfs/TestSaslFanOutOneBlockAsyncDFSOutput.java