* backing collection and the mutex are serializable.
 *
 * <p>If {@code null} is passed as the {@code mutex} parameter to any of this class's top-level
 * methods or inner class constructors, the created object uses itself as the synchronization mutex.
 *
 * <p>This class should be used by other collection classes only.
 *
 * @author Mike Bostock
 * @author Jared Levy
 */

    // Owner is subclassed
    assertHasTypeVariable(new From<Integer>() {}.new To<String>().type());
    assertHasTypeVariable(new From<T>() {}.new To<String>().type());

    // Inner is subclassed
    assertNoTypeVariable(new From<Integer>().new To<String>() {}.type());
    assertHasTypeVariable(new From<Integer>().new To<T>() {}.type());
    assertHasTypeVariable(new From<T>().new To<String>() {}.type());

  }

  @SuppressWarnings("unchecked")
  final Segment<K, V, E, S>[] newSegmentArray(int ssize) {
    return (Segment<K, V, E, S>[]) new Segment<?, ?, ?, ?>[ssize];
  }

  // Inner Classes

  /**
   * Segments are specialized versions of hash tables. This subclass inherits from ReentrantLock
   * opportunistically, just to simplify some locking and avoid separate construction.
   */

   * smaller). For example, partitioning an iterator containing {@code [a, b, c, d, e]} with a
   * partition size of 3 yields {@code [[a, b, c], [d, e]]} -- an outer iterator containing two
   * inner lists of three and two elements, all in the original order.
   *
   * <p>The returned lists implement {@link java.util.RandomAccess}.
   *

    // Owner is subclassed
    assertHasTypeVariable(new From<Integer>() {}.new To<String>().type());
    assertHasTypeVariable(new From<T>() {}.new To<String>().type());

    // Inner is subclassed
    assertNoTypeVariable(new From<Integer>().new To<String>() {}.type());
    assertHasTypeVariable(new From<Integer>().new To<T>() {}.type());
    assertHasTypeVariable(new From<T>().new To<String>() {}.type());