docs: public static <T> Collector<T, ?, Quantile> toQuantile(
  		final double quantile,
  		final ToDoubleFunction<? super T> mapper
  	) {
  		check(quantile);
  		requireNonNull(mapper);
  
  		return Collector.of(
  			() -> new Quantile(quantile),
  			(r, t) -> r.accept(mapper.applyAsDouble(t)),
  			Quantile::combine
  		);
  	}