docs: public static <T> Collector<T, ?, DoubleMoments>
  	toDoubleMoments(final ToDoubleFunction<? super T> mapper) {
  		requireNonNull(mapper);
  		return Collector.of(
  			DoubleMomentStatistics::new,
  			(a, b) -> a.accept(mapper.applyAsDouble(b)),
  			DoubleMomentStatistics::combine,
  			DoubleMoments::of
  		);
  	}