@TestOnly
  public boolean processKeys(@NotNull Processor<? super Key> processor) throws StorageException {
    try {
      clearCachedMappings(); // this will ensure that all new keys are made into the map
      return doProcessKeys(processor);
    }
    catch (IOException e) {
      throw new StorageException(e);
    }
    catch (RuntimeException e) {
      unwrapCauseAndRethrow(e);
      return false;
    }
  }
@TestOnly
  public boolean processKeys(@NotNull Processor<? super Key> processor)