code: @SuppressWarnings("unchecked") //
    public static <E> ImmutableMultiset<E> of(E e1, E e2) {
      return copyOfInternal(e1, e2);
    }
docs: Returns an immutable multiset containing the given elements, in order.
  
  @throws NullPointerException if any element is null
  @since 6.0 (source-compatible since 2.0)