code: public static <E> ImmutableSortedSet<E> copyOf(
        Comparator<? super E> comparator, Collection<? extends E> elements) {
      return copyOf(comparator, (Iterable<? extends E>) elements);
    }
docs: Returns an immutable sorted set containing the given elements sorted by the given {@code
  Comparator}. When multiple elements are equivalent according to {@code compareTo()}, only the
  first one specified is included.
  
  <p>Despite the method name, this method attempts to avoid actually copying the data when it is
  safe to do so. The exact circumstances under which a copy will or will not be performed are
  undocumented and subject to change.
  
  <p>This method is safe to use even when {@code elements} is a synchronized or concurrent
  collection that is currently being modified by another thread.
  
  @throws NullPointerException if {@code comparator} or any of {@code elements} is null
  @since 7.0 (source-compatible since 2.0)