* SetView}.
     */
    abstract int minSize();

    /**
     * Returns the {@link #minSize()} of {@code set} if it is a {@link SetView}, or the exact {@link
     * #size()} of {@code set} otherwise.
     */
    static int minSize(Set<?> set) {
      return set instanceof SetView ? ((SetView<?>) set).minSize() : set.size();
    }

    /**