@Override
    protected FileLocalStringEnumerator createStubIndexKeySerializationState(@NotNull DataOutput out, @NotNull Set<StubIndexKey<?, ?>> set) throws IOException {
      FileLocalStringEnumerator enumerator = new FileLocalStringEnumerator(true);
      for (StubIndexKey<?, ?> key : set) {
        enumerator.enumerate(key.getName());
      }
      enumerator.write(out);
      return enumerator;
    }
@Override
    protected FileLocalStringEnumerator createStubIndexKeySerializationState(@NotNull DataOutput out, @NotNull Set<StubIndexKey<?, ?>> set)