docs: @Override
    public StateRepository getStateRepositoryWithin(PersistenceSpaceIdentifier<?> identifier, String name)
        throws CachePersistenceException {
  
      PersistenceSpace persistenceSpace = getPersistenceSpace(identifier);
      if(persistenceSpace == null) {
        throw newCachePersistenceException(identifier);
      }
  
      FileBasedStateRepository stateRepository = new FileBasedStateRepository(
          FileUtils.createSubDirectory(persistenceSpace.identifier.persistentSpaceId.getRoot(), name));
      FileBasedStateRepository previous = persistenceSpace.stateRepositories.putIfAbsent(name, stateRepository);
      if (previous != null) {
        return previous;
      }
      return stateRepository;
    }