code: public static <C extends Comparable<?>> ImmutableRangeSet<C> unionOf(Iterable<Range<C>> ranges) {
      return copyOf(TreeRangeSet.create(ranges));
    }
docs: Returns an {@code ImmutableRangeSet} representing the union of the specified ranges.
  
  <p>This is the smallest {@code RangeSet} which encloses each of the specified ranges. Duplicate
  or connected ranges are permitted, and will be coalesced in the result.
  
  @since 21.0