@Override
    public Optional<RegionObserver> getRegionObserver() {
      return Optional.of(this);
    }
This class is for testing HBaseConnectionManager ServerBusyException. Be careful adding to this
class. It sets a low HBASE_CLIENT_PERSERVER_REQUESTS_THRESHOLD
hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestServerBusyException.java