static final Serialization.FieldSetter<? super ImmutableMultimap<?, ?>> MAP_FIELD_SETTER =
        Serialization.getFieldSetter(ImmutableMultimap.class, "map");
    static final Serialization.FieldSetter<? super ImmutableMultimap<?, ?>> SIZE_FIELD_SETTER =
        Serialization.getFieldSetter(ImmutableMultimap.class, "size");

    private FieldSettersHolder() {}
  }

          .put(ImmutableSortedMap.class, ImmutableSortedMap.of())
          .put(NavigableMap.class, Maps.unmodifiableNavigableMap(Maps.newTreeMap()))
          .put(Multimap.class, ImmutableMultimap.of())
          .put(ImmutableMultimap.class, ImmutableMultimap.of())
          .put(ListMultimap.class, ImmutableListMultimap.of())
          .put(ImmutableListMultimap.class, ImmutableListMultimap.of())

  }

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(ImmutableMultimap.of(), ImmutableMultimap.of())
        .addEqualityGroup(ImmutableMultimap.of(1, "a"), ImmutableMultimap.of(1, "a"))
        .addEqualityGroup(
            ImmutableMultimap.of(1, "a", 2, "b"), ImmutableMultimap.of(2, "b", 1, "a"))
        .testEquals();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection

   *
   * <p>Because an inverse of a list multimap can contain multiple pairs with the same key and
   * value, this method returns an {@code ImmutableListMultimap} rather than the {@code
   * ImmutableMultimap} specified in the {@code ImmutableMultimap} class.
   *
   * @since 11.0
   */
  @Override
  public ImmutableListMultimap<V, K> inverse() {
    ImmutableListMultimap<V, K> result = inverse;

    assertEquals("", j.join(ImmutableMultimap.of().entries()));
    assertEquals("", j.join(ImmutableMultimap.of().entries().iterator()));
    assertEquals(":", j.join(ImmutableMultimap.of("", "").entries()));
    assertEquals(":", j.join(ImmutableMultimap.of("", "").entries().iterator()));
    assertEquals("1:a;1:b", j.join(ImmutableMultimap.of("1", "a", "1", "b").entries()));

   *
   * <p>Because an inverse of a set multimap cannot contain multiple pairs with the same key and
   * value, this method returns an {@code ImmutableSetMultimap} rather than the {@code
   * ImmutableMultimap} specified in the {@code ImmutableMultimap} class.
   */
  @Override
  public ImmutableSetMultimap<V, K> inverse() {
    ImmutableSetMultimap<V, K> result = inverse;
    return (result == null) ? (inverse = invert()) : result;
  }

      derivedFeatures.remove(CollectionFeature.SERIALIZABLE);
    }
    return derivedFeatures;
  }

  private static final ImmutableMultimap<Feature<?>, Feature<?>> GET_FEATURE_MAP =
      ImmutableMultimap.<Feature<?>, Feature<?>>builder()
          .put(
              MapFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION,
              CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION)

    assertTrue(ArbitraryInstances.get(SortedMultiset.class).isEmpty());
    assertEquals(ImmutableMultimap.of(), ArbitraryInstances.get(Multimap.class));
    assertEquals(ImmutableMultimap.of(), ArbitraryInstances.get(ImmutableMultimap.class));
    assertTrue(ArbitraryInstances.get(SortedSetMultimap.class).isEmpty());
    assertEquals(ImmutableTable.of(), ArbitraryInstances.get(Table.class));

          .put(ImmutableSortedMap.class, ImmutableSortedMap.of())
          .put(NavigableMap.class, Maps.unmodifiableNavigableMap(Maps.newTreeMap()))
          .put(Multimap.class, ImmutableMultimap.of())
          .put(ImmutableMultimap.class, ImmutableMultimap.of())
          .put(ListMultimap.class, ImmutableListMultimap.of())
          .put(ImmutableListMultimap.class, ImmutableListMultimap.of())

   *
   * <p>Because an inverse of a list multimap can contain multiple pairs with the same key and
   * value, this method returns an {@code ImmutableListMultimap} rather than the {@code
   * ImmutableMultimap} specified in the {@code ImmutableMultimap} class.
   *
   * @since 11.0
   */
  @Override
  public ImmutableListMultimap<V, K> inverse() {
    ImmutableListMultimap<V, K> result = inverse;