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