* provided key-value mapping, this method has no effect.
   *
   * <p>Note that a successful call to this method could cause the size of the bimap to increase by
   * one, stay the same, or even decrease by one.
   *
   * <p><b>Warning:</b> If an existing entry with this value is removed, the key for that entry is
   * discarded and not returned.
   *

 *       as that of its keys. This is sometimes called an "invertible map," since the restriction on
 *       values enables it to support an {@linkplain BiMap#inverse inverse view} -- which is another
 *       instance of {@code BiMap}.
 *   <dt>{@link Table}
 *   <dd>A new type, which is similar to {@link java.util.Map}, but which indexes its values by an
 *       ordered pair of keys, a row key and column key.
 *   <dt>{@link Multiset}

  public void testAsMapGetImplementsSet() {
    for (K key : multimap().keySet()) {
      assertTrue(multimap().asMap().get(key) instanceof Set);
    }
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testAsMapRemoveImplementsSet() {
    List<K> keys = new ArrayList<>(multimap().keySet());
    for (K key : keys) {
      resetCollection();
      assertTrue(multimap().asMap().remove(key) instanceof Set);
    }
  }

 *
 * {@snippet :
 * LoadingCache<Key, Graph> graphs = CacheBuilder.newBuilder()
 *     .maximumSize(10000)
 *     .expireAfterWrite(Duration.ofMinutes(10))
 *     .removalListener(MY_LISTENER)
 *     .build(
 *         new CacheLoader<Key, Graph>() {
 *           public Graph load(Key key) throws AnyException {
 *             return createExpensiveGraph(key);
 *           }
 *         });
 * }
 *

)

private class ConcurrentMultiMap<K, V> {
    private val map = ConcurrentHashMap<K, MutableSet<V>>()

    fun add(key: K, value: V) =
        map.computeIfAbsent(key, { _ -> ConcurrentHashMap.newKeySet() }).add(value)

    fun getOrEmpty(key: K): Set<V> = map[key] ?: emptySet()
}

abstract class TestFilesCleanupService @Inject constructor(
    private val fileSystemOperations: FileSystemOperations,

  @Override
  public boolean remove(@Nullable Object key, @Nullable Object value) {
    return delegate().remove(key, value);
  }

  @CanIgnoreReturnValue
  @Override
  public Collection<V> removeAll(@Nullable Object key) {
    return delegate().removeAll(key);
  }

  @CanIgnoreReturnValue
  @Override
  public Collection<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {

  @Override
  public boolean remove(@Nullable Object key, @Nullable Object value) {
    return delegate().remove(key, value);
  }

  @CanIgnoreReturnValue
  @Override
  public Collection<V> removeAll(@Nullable Object key) {
    return delegate().removeAll(key);
  }

  @CanIgnoreReturnValue
  @Override
  public Collection<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {

    getMap()
        .replaceAll(
            (K k, V v) -> {
              int index = keys().asList().indexOf(k);
              return values().asList().get(index + 1);
            });
    List<Entry<K, V>> orderedEntries = getOrderedElements();
    int index = 0;
    for (K key : getMap().keySet()) {
      assertEquals(orderedEntries.get(index).getKey(), key);
      index++;
    }
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)

        String key = virtualHostHelper.getVirtualHostKey();
        assertEquals("", key);

        // Matching host header
        request.addHeader("Host", "example.com");
        key = virtualHostHelper.getVirtualHostKey();
        assertEquals("", key); // Still empty due to caching

        // Test caching by calling again - should return cached value
        key = virtualHostHelper.getVirtualHostKey();

  @Override
  public @Nullable V put(K key, V value) {
    checkNotNull(key);
    checkNotNull(value);
    int hash = hash(key);
    return segmentFor(hash).put(key, hash, value, false);
  }

  @Override
  public @Nullable V putIfAbsent(K key, V value) {
    checkNotNull(key);
    checkNotNull(value);
    int hash = hash(key);
    return segmentFor(hash).put(key, hash, value, true);
  }