docs: public PersistenceBrokerInternal getBrokerInternal()
      {
          if (broker == null || broker.isClosed())
          {
              checkOpen();
              try
              {
                  checkForDB();
                  broker = PersistenceBrokerFactoryFactory.instance().createPersistenceBroker(curDB.getPBKey());
              }
              catch (PBFactoryException e)
              {
                  log.error("Cannot obtain PersistenceBroker from PersistenceBrokerFactory, " +
                          "found PBKey was " + curDB.getPBKey(), e);
                  throw new PersistenceBrokerException(e);
              }
          }
          return broker;
      }