}
    }

    @Override
    public Set<Map.Entry<K, Collection<V>>> entrySet() {
      synchronized (mutex) {
        if (asMapEntrySet == null) {
          asMapEntrySet = new SynchronizedAsMapEntries<>(delegate().entrySet(), mutex);
        }
        return asMapEntrySet;
      }
    }

    @Override
    public Collection<Collection<V>> values() {
      synchronized (mutex) {

      }
    }

    @Override
    public Set<Map.Entry<K, Collection<V>>> entrySet() {
      synchronized (mutex) {
        if (asMapEntrySet == null) {
          asMapEntrySet = new SynchronizedAsMapEntries<>(delegate().entrySet(), mutex);
        }
        return asMapEntrySet;
      }
    }

    @Override
    public Collection<Collection<V>> values() {
      synchronized (mutex) {

    assertThat(cache.asMap().keySet().contains(20)).isTrue();
    assertThat(cache.asMap().keySet().contains(5)).isTrue();
    assertThat(cache.asMap().keySet().contains(10)).isFalse();
  }

  @Test
  public void asMapEntrySet() {
    Cache<Integer, Integer> cache =
        CacheBuilder.newBuilder().expireAfterWrite(1000, MILLISECONDS).ticker(fakeTicker).build();

    cache.put(10, 20);
    fakeTicker.advance(500, MILLISECONDS);