long nanos = expirationNanos;
      long now = System.nanoTime();
      if (nanos == 0 || now - nanos >= 0) {
        synchronized (this) {
          if (nanos == expirationNanos) { // recheck for lost race
            T t = delegate.get();
            value = t;
            nanos = now + durationNanos;
            // In the very unlikely event that nanos is 0, set it to 1;

  @GwtCompatible(serializable = true)
  public final <S extends @Nullable T> Equivalence<Iterable<S>> pairwise() {
    // Ideally, the returned equivalence would support Iterable<? extends T>. However,
    // the need for this is so rare that it's not worth making callers deal with the ugly wildcard.
    return new PairwiseEquivalence<>(this);
  }

  /**
   * Returns a predicate that evaluates to true if and only if the input is equivalent to {@code

            }
            // Make sure (whatever extra priority is set) that resolver file/apache is selected
            configProps.put(FILE_TRANSPORTER_PRIORITY_KEY, RESOLVER_MAX_PRIORITY);
            configProps.put(APACHE_HTTP_TRANSPORTER_PRIORITY_KEY, RESOLVER_MAX_PRIORITY);
        } else if (MAVEN_RESOLVER_TRANSPORT_WAGON.equals(transport)) {
            // Make sure (whatever extra priority is set) that wagon is selected

        result = repositorySystem.resolve(request);
        resolutionErrorHandler.throwErrors(request, result);
        assertEquals(1, result.getArtifacts().size());

        //
        // Put in a bogus file to make sure missing files cause the resolution to fail.
        //
        file = new File(getBasedir(), "src/test/repository-system/maven-monkey-2.1.0.jar");
        assertFalse(file.exists());

  }

  @SuppressWarnings({"AndroidJdkLibsChecker", "Java7ApiChecker"})
  @IgnoreJRERequirement // helper for toImmutableSortedMultiset
  /*
   * If we make these calls inline inside toImmutableSortedMultiset, we get an Animal Sniffer error,
   * despite the @IgnoreJRERequirement annotation there. My assumption is that, because javac

    @Test
    void testMirrorStopOnFirstMatch() {
        // exact matches win first
        Mirror mirrorA2 = newMirror("a2", "a,b", "http://a2");
        Mirror mirrorA = newMirror("a", "a", "http://a");
        // make sure repeated entries are skipped
        Mirror mirrorA3 = newMirror("a", "a", "http://a3");

        Mirror mirrorB = newMirror("b", "b", "http://b");
        Mirror mirrorC = newMirror("c", "d,e", "http://de");

  //    assigned prior to calling addListener, and addListener happens-before any invocation of the
  //    listener. Notably, this means that 'volatile' is unnecessary to make 'inputFuture' visible
  //    to the listener.
  //
  // 2. In done() where we may propagate cancellation to the input. In this case it is _not_ fine.

    /*
     * This code performs one System.nanoTime() more than necessary, and in return, the time to
     * execute Queue#drainTo is not added *on top* of waiting for the timeout (which could make
     * the timeout arbitrarily inaccurate, given a queue that is slow to drain).
     */
    long deadline = System.nanoTime() + unit.toNanos(timeout);
    int added = 0;
    while (added < numElements) {