@Override
    synchronized boolean removeKey(Integer keyId) {
      boolean b = super.removeKey(keyId);
      if (b) {
        latch.countDown();
      }
      return b;
    }
Test the synchronization of token authentication master keys through ZKSecretWatcher
hbase-server/src/test/java/org/apache/hadoop/hbase/security/token/TestZKSecretWatcher.java