* Tasks execute with the same happens-before order that the function calls to {@link #submit} and
 * {@link #submitAsync} that submitted those tasks had.
 *
 * <p>This class has limited support for cancellation and other "early completions":
 *
 * <ul>
 *   <li>While calls to {@code submit} and {@code submitAsync} return a {@code Future} that can be
 *       cancelled, cancellation never propagates to a task that has started to run -- neither to

  final boolean threadStarted;

  /** Constructs a new queue. */
  public FinalizableReferenceQueue() {
    // We could start the finalizer lazily, but I'd rather it blow up early.
    queue = new ReferenceQueue<>();
    frqRef = new PhantomReference<>(this, queue);
    boolean threadStarted = false;
    try {
      startFinalizer.invoke(null, FinalizableReference.class, queue, frqRef);

  final boolean threadStarted;

  /** Constructs a new queue. */
  public FinalizableReferenceQueue() {
    // We could start the finalizer lazily, but I'd rather it blow up early.
    queue = new ReferenceQueue<>();
    frqRef = new PhantomReference<>(this, queue);
    boolean threadStarted = false;
    try {
      startFinalizer.invoke(null, FinalizableReference.class, queue, frqRef);

  public static final String CROSS_ORIGIN_RESOURCE_POLICY = "Cross-Origin-Resource-Policy";
  /**
   * The HTTP <a href="https://tools.ietf.org/html/rfc8470">{@code Early-Data}</a> header field
   * name.
   *
   * @since 27.0
   */
  public static final String EARLY_DATA = "Early-Data";
  /** The HTTP {@code Expect} header field name. */
  public static final String EXPECT = "Expect";
  /** The HTTP {@code From} header field name. */

        || (a == b) // needed to ensure that infinities equal themselves
        || (Double.isNaN(a) && Double.isNaN(b));
  }

  /**
   * Compares {@code a} and {@code b} "fuzzily," with a tolerance for nearly-equal values.
   *
   * <p>This method is equivalent to {@code fuzzyEquals(a, b, tolerance) ? 0 : Double.compare(a,
   * b)}. In particular, like {@link Double#compare(double, double)}, it treats all NaN values as

      fail();
    } catch (IndexOutOfBoundsException expected) {
    }
  }

  /*
   * Full and proper black-box testing of a Stream-returning method is extremely involved, and is
   * overkill when nearly all Streams are produced using well-tested JDK calls. So, we cheat and
   * just test that the toArray() contents are as expected.
   */
  public void testStream() {
    assertThat(FluentIterable.of().stream()).isEmpty();

   * {@code readable}. Note that this method may not fully consume the contents of {@code readable}
   * if the processor stops processing early.
   *
   * @throws IOException if an I/O error occurs
   * @since 14.0
   */
  @CanIgnoreReturnValue // some processors won't return a useful result
  @ParametricNullness

 * API</h2>
 *
 * <p>The successor to Guava's caching API is <a
 * href="https://github.com/ben-manes/caffeine/wiki">Caffeine</a>. Its API is designed to make it a
 * nearly drop-in replacement. It requires Java 8+, and is not available for Android or GWT/J2CL,
 * and may have <a href="https://github.com/ben-manes/caffeine/wiki/Guava">different (usually

      Executor executor) {
    return AbstractCatchingFuture.create(input, exceptionType, fallback, executor);
  }

  /**
   * Returns a future that delegates to another but will finish early (via a {@link
   * TimeoutException} wrapped in an {@link ExecutionException}) if the specified duration expires.
   *
   * <p>The delegate future is interrupted and cancelled if it times out.
   *