code: @SuppressWarnings("rawtypes")
      public static <T extends Comparable> Collector<T, ?, List<T>> maxAll() {
          return maxAll(Fn.naturalOrder());
      }
docs: It's copied from StreamEx: https://github.com/amaembo/streamex under Apache License v2 and may be modified.
  <br />
  
  Returns a {@code Collector} which finds all the elements which are equal
  to each other and bigger than any other element according to the natural
  order. The found elements are collected to {@link List}.
  
  @param <T> the type of the input elements
  @return a {@code Collector} which finds all the maximal elements and
  collects them to the {@code List}.
  @see #maxAll(Comparator)
  @see #maxAll(Collector)