* @param map the sequenced map
     * @return the first entry, or null if the map is empty
     * @since Java 21
     */
    public static <K, V> Map.Entry<K, V> firstEntry(final SequencedMap<K, V> map) {
        return map.isEmpty() ? null : map.firstEntry();
    }

    /**
     * Returns the last entry of a sequenced map.
     *
     * @param <K> the key type
     * @param <V> the value type