code: @Override
    public void close()
    {
      super.close();
      facts.clear();
      indexAndOffsets.clear();
  
      if (selectors != null) {
        selectors.clear();
      }
  
      Closer c = Closer.create();
      aggBuffers.forEach(c::register);
      try {
        c.close();
      }
      catch (IOException e) {
        throw new RuntimeException(e);
      }
      aggBuffers.clear();
    }
docs: NOTE: This is NOT thread-safe with add... so make sure all the adding is DONE before closing