* Returns a {@code Comparator<Boolean>} that sorts {@code true} before {@code false}.
   *
   * <p>This is particularly useful in Java 8+ in combination with {@code Comparator.comparing},
   * e.g. {@code Comparator.comparing(Foo::hasBar, trueFirst())}.
   *
   * @since 21.0
   */
  public static Comparator<Boolean> trueFirst() {
    return BooleanComparator.TRUE_FIRST;
  }

  /**

   * Returns a {@code Comparator<Boolean>} that sorts {@code true} before {@code false}.
   *
   * <p>This is particularly useful in Java 8+ in combination with {@code Comparator.comparing},
   * e.g. {@code Comparator.comparing(Foo::hasBar, trueFirst())}.
   *
   * @since 21.0
   */
  public static Comparator<Boolean> trueFirst() {
    return BooleanComparator.TRUE_FIRST;
  }

  /**

  }

  public void testAsSet_absentIsImmutable() {
    Set<Object> absentAsSet = Optional.absent().asSet();
    assertThrows(UnsupportedOperationException.class, () -> absentAsSet.add("foo"));
  }

  public void testTransform_absent() {
    assertEquals(Optional.absent(), Optional.absent().transform(Functions.identity()));

        .build()
    val request = Request("http://android.com/foo".toHttpUrl())
    val response = client.newCall(request).execute()
    assertThat(response.body.string()).isEqualTo("response body")
    val get1 = server.takeRequest()
    assertThat(get1.requestLine).isEqualTo("GET http://android.com/foo HTTP/1.1")
    assertThat(get1.headers["Proxy-Authorization"]).isNull()

      implements TestListGenerator<Entry<String, Integer>> {

    @Override
    public SampleElements<Entry<String, Integer>> samples() {
      return new SampleElements<>(
          mapEntry("foo", 5),
          mapEntry("bar", 3),
          mapEntry("baz", 17),
          mapEntry("quux", 1),
          mapEntry("toaster", -2));
    }

    @SuppressWarnings("unchecked")
    @Override

 * </ul>
 *
 * <h4>Example usage</h4>
 *
 * {@snippet :
 * class Foo {
 *   private static final ImmutableSet<String> RESERVED_CODES =
 *       ImmutableSet.of("AZ", "CQ", "ZX");
 *
 *   private final ImmutableSet<String> codes;
 *
 *   public Foo(Iterable<String> codes) {
 *     this.codes = ImmutableSet.copyOf(codes);

 * for the following multimap definition:
 *
 * {@snippet :
 * Multimap<K, V> multimap = LinkedListMultimap.create();
 * multimap.put(key1, foo);
 * multimap.put(key2, bar);
 * multimap.put(key1, baz);
 * }
 *
 * ... the iteration order for {@link #keys()} is {@code [key1, key2, key1]}, and similarly for

     * <p>
     * The {@link Traverser} returned by this method uses the path where the specified class can be referenced by its FQN as the root.
     * For example, if the specified class is <code>foo.Bar</code> and its class file is located at <code>classes/foo/Bar.class</code>,
     * the {@link Traverser} returned by this method will handle the collection of resources under the <code>classes</code> directory.
     * </p>
     *

 * when {@code compare} is called on the above ordering:
 *
 * <ol>
 *   <li>First, if only one {@code Foo} is null, that null value is treated as <i>greater</i>
 *   <li>Next, non-null {@code Foo} values are passed to {@code getBarFunction} (we will be
 *       comparing {@code Bar} values from now on)

   * ...
   * synchronized (queue) {  // Must synchronize on queue!
   *   Iterator<E> i = queue.iterator(); // Must be in synchronized block
   *   while (i.hasNext()) {
   *     foo(i.next());
   *   }
   * }
   * }
   *
   * <p>Failure to follow this advice may result in non-deterministic behavior.
   *
   * <p>The returned queue will be serializable if the specified queue is serializable.