* around a {@link java.util.TreeMap}.
 *
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
public final class ImmutableSortedMap<K, V> extends ForwardingImmutableMap<K, V>
    implements SortedMap<K, V> {

  @SuppressWarnings("unchecked")
  static final Comparator<?> NATURAL_ORDER = Ordering.natural();