docs: private void validateFilters() {
      Set<String> ids = new HashSet<String>();
      for (Filter filter : filters) {
        ids.add(filter.getId());
      }
  
      for(Metric metric : metrics) {
        if (metric.getFilter() != null && 
            !metric.getFilter().isEmpty() && 
            !ids.contains(metric.getFilter())) {
          throw new IllegalArgumentException(
              String.format("unrecognized filter id %s in metric %s",
                  metric.getFilter(), metric.getId()));
        }
      }
    }