*   while (it.hasNext()) {
   *     foo(it.next());
   *   }
   * }
   * }</pre>
   *
   * <p>or:
   *
   * <pre>{@code
   * NavigableMap<K, V> map = synchronizedNavigableMap(new TreeMap<K, V>());
   * NavigableMap<K, V> map2 = map.subMap(foo, false, bar, true);
   *
   * // Needn't be in synchronized block