docs: private void startInternalCache() {
        if (knownClassesCache == null) {
           synchronized (this) {
              if (knownClassesCache == null) {
                 internalCacheRegistry.registerInternalCache(QUERY_KNOWN_CLASSES_CACHE_NAME, getInternalCacheConfig(), EnumSet.of(InternalCacheRegistry.Flag.PERSISTENT));
                 Cache<KeyValuePair<String, Class<?>>, Boolean> knownClassesCache = SecurityActions.getCache(cacheManager, QUERY_KNOWN_CLASSES_CACHE_NAME);
                 this.knownClassesCache = knownClassesCache.getAdvancedCache().withFlags(Flag.SKIP_LOCKING, Flag.IGNORE_RETURN_VALUES);
                 transactionHelper = new TransactionHelper(this.knownClassesCache.getTransactionManager());
              }
           }
        }
     }