docs: public static Map<String, Number> buildStatsMap(
              Collection<Number> numberCollection) {
          return JMMap.newChangedKeyMap(
                  getOptional(numberCollection).map(NumberSummaryStatistics::of)
                          .map(NumberSummaryStatistics::getStatsFieldMap)
                          .orElseGet(Collections::emptyMap), StatsField::name);
      }