@RetainedWith
  transient AbstractBiMap<V, K> inverse;

  /** Package-private constructor for creating a map-backed bimap. */
  AbstractBiMap(Map<K, V> forward, Map<V, K> backward) {
    setDelegates(forward, backward);
  }

  /** Private constructor for inverse bimap. */
  private AbstractBiMap(Map<K, V> backward, AbstractBiMap<V, K> forward) {
    delegate = backward;
    inverse = forward;
  }

  @RetainedWith
  transient AbstractBiMap<V, K> inverse;

  /** Package-private constructor for creating a map-backed bimap. */
  AbstractBiMap(Map<K, V> forward, Map<V, K> backward) {
    setDelegates(forward, backward);
  }

  /** Private constructor for inverse bimap. */
  private AbstractBiMap(Map<K, V> backward, AbstractBiMap<V, K> forward) {
    delegate = backward;
    inverse = forward;
  }

   * as implementation details.
   *
   * <p>Since the bimap is immutable, ImmutableBiMap doesn't require special logic for keeping the
   * bimap and its inverse in sync during serialization, the way AbstractBiMap does.
   */
  @J2ktIncompatible // serialization
  private static class SerializedForm<K, V> extends ImmutableMap.SerializedForm<K, V> {
    SerializedForm(ImmutableBiMap<K, V> bimap) {
      super(bimap);
    }

   * as implementation details.
   *
   * <p>Since the bimap is immutable, ImmutableBiMap doesn't require special logic for keeping the
   * bimap and its inverse in sync during serialization, the way AbstractBiMap does.
   */
  @J2ktIncompatible // serialization
  private static class SerializedForm<K, V> extends ImmutableMap.SerializedForm<K, V> {
    SerializedForm(ImmutableBiMap<K, V> bimap) {
      super(bimap);
    }