/**
   * Returns the inverse view of this bimap, which maps each of this bimap's values to its
   * associated key. The two bimaps are backed by the same data; any changes to one will appear in
   * the other.
   *
   * <p><b>Note:</b> There is no guaranteed correspondence between the iteration order of a bimap
   * and that of its inverse.
   *
   * @return the inverse view of this bimap
   */
  BiMap<V, K> inverse();

      ImmutableBiMap<K, V> bimap = (ImmutableBiMap<K, V>) map;
      // TODO(lowasser): if we need to make a copy of a BiMap because the
      // forward map is a view, don't make a copy of the non-view delegate map
      if (!bimap.isPartialView()) {
        return bimap;
      }
    }
    return copyOf(map.entrySet());
  }

  /**

      ImmutableBiMap<K, V> bimap = (ImmutableBiMap<K, V>) map;
      // TODO(lowasser): if we need to make a copy of a BiMap because the
      // forward map is a view, don't make a copy of the non-view delegate map
      if (!bimap.isPartialView()) {
        return bimap;
      }
    }
    return copyOf(map.entrySet());
  }

  /**

   */
  public static <A, B> Converter<A, B> asConverter(BiMap<A, B> bimap) {
    return new BiMapConverter<>(bimap);
  }

  private static final class BiMapConverter<A, B> extends Converter<A, B> implements Serializable {
    private final BiMap<A, B> bimap;

    BiMapConverter(BiMap<A, B> bimap) {
      this.bimap = checkNotNull(bimap);
    }

    @Override
    protected B doForward(A a) {

   */
  public static <A, B> Converter<A, B> asConverter(BiMap<A, B> bimap) {
    return new BiMapConverter<>(bimap);
  }

  private static final class BiMapConverter<A, B> extends Converter<A, B> implements Serializable {
    private final BiMap<A, B> bimap;

    BiMapConverter(BiMap<A, B> bimap) {
      this.bimap = checkNotNull(bimap);
    }

    @Override
    protected B doForward(A a) {

    EnumHashBiMap<Currency, String> bimap1 = EnumHashBiMap.create(Currency.class);
    bimap1.put(Currency.DOLLAR, "dollar");
    EnumHashBiMap<Currency, String> bimap2 = EnumHashBiMap.create(bimap1);
    assertEquals("dollar", bimap2.get(Currency.DOLLAR));
    assertEquals(bimap1, bimap2);
    bimap2.inverse().put("franc", Currency.FRANC);
    assertEquals("franc", bimap2.get(Currency.FRANC));

    assertEquals(bimap1, bimap2);
    bimap2.inverse().put(Country.SWITZERLAND, Currency.FRANC);
    assertEquals(Country.SWITZERLAND, bimap2.get(Currency.FRANC));
    assertThat(bimap1.get(Currency.FRANC)).isNull();
    assertFalse(bimap2.equals(bimap1));

    /* Test that it can be empty. */
    EnumBiMap<Currency, Country> emptyBimap = EnumBiMap.create(Currency.class, Country.class);

  @J2ktIncompatible // Synchronized
  public void testSynchronizedBiMap() {
    BiMap<String, Integer> bimap = HashBiMap.create();
    bimap.put("one", 1);
    BiMap<String, Integer> sync = Maps.synchronizedBiMap(bimap);
    bimap.put("two", 2);
    sync.put("three", 3);
    assertEquals(ImmutableSet.of(1, 2, 3), bimap.inverse().keySet());
    assertEquals(ImmutableSet.of(1, 2, 3), sync.inverse().keySet());
  }

  @J2ktIncompatible // Synchronized
  public void testSynchronizedBiMap() {
    BiMap<String, Integer> bimap = HashBiMap.create();
    bimap.put("one", 1);
    BiMap<String, Integer> sync = Maps.synchronizedBiMap(bimap);
    bimap.put("two", 2);
    sync.put("three", 3);
    assertEquals(ImmutableSet.of(1, 2, 3), bimap.inverse().keySet());
    assertEquals(ImmutableSet.of(1, 2, 3), sync.inverse().keySet());
  }

      extends AbstractSet<T> {
    final HashBiMap<K, V> biMap;

    View(HashBiMap<K, V> biMap) {
      this.biMap = biMap;
    }

    @ParametricNullness
    abstract T forEntry(int entry);

    @Override
    public final Iterator<T> iterator() {
      return new Iterator<T>() {
        private int index = biMap.firstInInsertionOrder;
        private int indexToRemove = ABSENT;