code: public static Collector<MonetaryAmount, MonetarySummaryStatistics, MonetarySummaryStatistics> summarizingMonetary(
              CurrencyUnit currencyUnit){
  		Supplier<MonetarySummaryStatistics> supplier = () -> new DefaultMonetarySummaryStatistics(currencyUnit);
  		return Collector.of(supplier, MonetarySummaryStatistics::accept, MonetarySummaryStatistics::combine);
      }
docs: Creates a the summary of MonetaryAmounts.
  @param currencyUnit the target {@link javax.money.CurrencyUnit}
  @return the MonetarySummaryStatistics