private transient Map<K, V> delegate;

  @SuppressWarnings("nullness:initialization.field.uninitialized") // For J2KT (lateinit)
  @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 transient Map<K, V> delegate;

  @SuppressWarnings("nullness:initialization.field.uninitialized") // For J2KT (lateinit)
  @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);
  }