docs: private void transformRollupQueryToDownSampler()  {
      
      if (rollup_query != null) {
        // TODO - clean up and handle fill
        downsampler = new DownsamplingSpecification(
            rollup_query.getRollupInterval().getIntervalSeconds() * 1000, 
            rollup_query.getRollupAgg(),
            (downsampler != null ? downsampler.getFillPolicy() : 
              FillPolicy.ZERO));
        rollup_query = null;
      }
    }