cache.put("a", "b");
    cache.asMap().computeIfAbsent("a", k -> "c");
    assertTrue(notifications.toString(), notifications.isEmpty());
  }

  public void testCopyEntry_computing() {
    final CountDownLatch startSignal = new CountDownLatch(1);
    final CountDownLatch computingSignal = new CountDownLatch(1);
    final CountDownLatch doneSignal = new CountDownLatch(2);

    map.put("quux", "quux");
    assertFalse(map.values() instanceof Set);
    assertTrue(map.values().removeAll(ImmutableSet.of("bar")));
    assertEquals(1, map.size());
  }

  public void testCopyEntry_computing() {
    final CountDownLatch startSignal = new CountDownLatch(1);
    final CountDownLatch computingSignal = new CountDownLatch(1);
    final CountDownLatch doneSignal = new CountDownLatch(2);

  final Segment<K, V>[] segments;

  /** The concurrency level. */
  final int concurrencyLevel;

  /** Strategy for comparing keys. */
  final Equivalence<Object> keyEquivalence;

  /** Strategy for comparing values. */
  final Equivalence<Object> valueEquivalence;

  /** Strategy for referencing keys. */
  final Strength keyStrength;

   * (Specifically, {@code directExecutor} functions should avoid heavyweight operations inside
   * {@code AsyncClosingFunction.apply}. Any heavyweight operations should occur in other threads
   * responsible for completing the returned {@code ClosingFuture}.)
   *
   * <p>After calling this method, you may not call {@link #finishToFuture()}, {@link
   * #finishToValueAndCloser(ValueAndCloserConsumer, Executor)}, or any other derivation method on

  final Segment<K, V>[] segments;

  /** The concurrency level. */
  final int concurrencyLevel;

  /** Strategy for comparing keys. */
  final Equivalence<Object> keyEquivalence;

  /** Strategy for comparing values. */
  final Equivalence<Object> valueEquivalence;

  /** Strategy for referencing keys. */
  final Strength keyStrength;