static <K extends @Nullable Object, V extends @Nullable Object> void writeMultimap(
      Multimap<K, V> multimap, ObjectOutputStream stream) throws IOException {
    stream.writeInt(multimap.asMap().size());
    for (Map.Entry<K, Collection<V>> entry : multimap.asMap().entrySet()) {
      stream.writeObject(entry.getKey());
      stream.writeInt(entry.getValue().size());
      for (V value : entry.getValue()) {
        stream.writeObject(value);

    Map<String, Integer> map = Maps.asMap(strings, LENGTH_FUNCTION);
    assertEquals(ImmutableMap.of("one", 3, "two", 3, "three", 5), map);
    assertEquals(Integer.valueOf(3), map.remove("two"));
    assertThat(strings).containsExactly("one", "three").inOrder();
  }

  public void testAsMapEmpty() {
    Set<String> strings = ImmutableSet.of();
    Map<String, Integer> map = Maps.asMap(strings, LENGTH_FUNCTION);

    }

    /**
     * Stores another multimap's entries in the built multimap. The generated multimap's key and
     * value orderings correspond to the iteration ordering of the {@code multimap.asMap()} view,
     * with new keys and values following any existing keys and values.
     *
     * @throws NullPointerException if any key or value in {@code multimap} is null. The builder is
     *     left in an invalid state.

    Map<String, Integer> map = Maps.asMap(strings, LENGTH_FUNCTION);
    assertEquals(ImmutableMap.of("one", 3, "two", 3, "three", 5), map);
    assertEquals(Integer.valueOf(3), map.remove("two"));
    assertThat(strings).containsExactly("one", "three").inOrder();
  }

  public void testAsMapEmpty() {
    Set<String> strings = ImmutableSet.of();
    Map<String, Integer> map = Maps.asMap(strings, LENGTH_FUNCTION);

    }

    /**
     * Stores another multimap's entries in the built multimap. The generated multimap's key and
     * value orderings correspond to the iteration ordering of the {@code multimap.asMap()} view,
     * with new keys and values following any existing keys and values.
     *
     * @throws NullPointerException if any key or value in {@code multimap} is null. The builder is
     *     left in an invalid state.

    // add a non-serializable entry
    one.getUnchecked(new Object());
    assertThat(one.size()).isEqualTo(1);
    assertThat(one.asMap().isEmpty()).isFalse();
    LocalLoadingCache<Object, Object> two = SerializableTester.reserialize(one);
    assertThat(two.size()).isEqualTo(0);
    assertThat(two.asMap().isEmpty()).isTrue();

    LocalCache<Object, Object> localCacheOne = one.localCache;

    // add a non-serializable entry
    one.getUnchecked(new Object());
    assertThat(one.size()).isEqualTo(1);
    assertThat(one.asMap().isEmpty()).isFalse();
    LocalLoadingCache<Object, Object> two = SerializableTester.reserialize(one);
    assertThat(two.size()).isEqualTo(0);
    assertThat(two.asMap().isEmpty()).isTrue();

    LocalCache<Object, Object> localCacheOne = one.localCache;