private @NotNull DataEnumeratorEx<String> openNameStorage() throws IOException {
    myOpenFile = myFile.get();
    if (myOpenFile == null) {
      return new InMemoryDataEnumerator<>();
    }

    return CreationTimeOptions.threadLocalOptions()
      .readOnly(myUnmodifiable)
      .with(() -> {
        return new PersistentStringEnumerator(myOpenFile, /*cacheLastMapping: */ true);
      });
  }
private @NotNull DataEnumeratorEx<String> openNameStorage()