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