docs: public VisualizerContext newContext(ResultHierarchy hier, Result start) {
      Collection<Relation<?>> rels = ResultUtil.filterResults(hier, Relation.class);
      for(Relation<?> rel : rels) {
        if(samplesize == 0) {
          continue;
        }
        if(!ResultUtil.filterResults(hier, rel, SamplingResult.class).isEmpty()) {
          continue;
        }
        if(rel.size() > samplesize) {
          SamplingResult sample = new SamplingResult(rel);
          sample.setSample(DBIDUtil.randomSample(sample.getSample(), samplesize, rnd));
          ResultUtil.addChildResult(rel, sample);
        }
      }
      return new VisualizerContext(hier, start, stylelib, factories);
    }