*
   * @since 16.0
   */
  public static <K0 extends Enum<K0>> MultimapBuilderWithKeys<K0> enumKeys(Class<K0> keyClass) {
    checkNotNull(keyClass);
    return new MultimapBuilderWithKeys<K0>() {
      @SuppressWarnings("unchecked")
      @Override
      <K extends K0, V extends @Nullable Object> Map<K, Collection<V>> createMap() {
        // K must actually be K0, since enums are effectively final

   *
   * @since 16.0
   */
  public static <K0 extends Enum<K0>> MultimapBuilderWithKeys<K0> enumKeys(Class<K0> keyClass) {
    checkNotNull(keyClass);
    return new MultimapBuilderWithKeys<K0>() {
      @SuppressWarnings("unchecked")
      @Override
      <K extends K0, V extends @Nullable Object> Map<K, Collection<V>> createMap() {
        // K must actually be K0, since enums are effectively final

    assertTrue(multimap().putAll(k0(), newArrayList(v3(), v4())::iterator));
    assertGet(k0(), v0(), v3(), v4());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutAllNonEmptyCollectionOnPresentKey() {
    assertTrue(multimap().putAll(k0(), newArrayList(v3(), v4())));
    assertGet(k0(), v0(), v3(), v4());
  }

  @MapFeature.Require(SUPPORTS_PUT)

    assertNull(navigableMap.lowerEntry(k0()));
    assertNull(navigableMap.lowerKey(k0()));
    assertNull(navigableMap.floorEntry(k0()));
    assertNull(navigableMap.floorKey(k0()));
    assertNull(navigableMap.ceilingEntry(k0()));
    assertNull(navigableMap.ceilingKey(k0()));
    assertNull(navigableMap.higherEntry(k0()));
    assertNull(navigableMap.higherKey(k0()));
  }

  @CollectionSize.Require(ZERO)

    assertNull(navigableMap.lowerEntry(k0()));
    assertNull(navigableMap.lowerKey(k0()));
    assertNull(navigableMap.floorEntry(k0()));
    assertNull(navigableMap.floorKey(k0()));
    assertNull(navigableMap.ceilingEntry(k0()));
    assertNull(navigableMap.ceilingKey(k0()));
    assertNull(navigableMap.higherEntry(k0()));
    assertNull(navigableMap.higherKey(k0()));
  }

  @CollectionSize.Require(ZERO)

    assertTrue(multimap().putAll(k0(), newArrayList(v3(), v4())::iterator));
    assertGet(k0(), v0(), v3(), v4());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutAllNonEmptyCollectionOnPresentKey() {
    assertTrue(multimap().putAll(k0(), newArrayList(v3(), v4())));
    assertGet(k0(), v0(), v3(), v4());
  }

  @MapFeature.Require(SUPPORTS_PUT)

    assertGet(k0(), v0());

    assertTrue(multimap().put(k0(), v3()));

    assertGet(k0(), v0(), v3());
    assertEquals(size + 1, multimap().size());
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutTwoElements() {
    int size = getNumElements();

    List<V> values = copyToList(multimap().get(k0()));

    assertTrue(multimap().put(k0(), v1()));

    assertGet(k0(), v0());

    assertTrue(multimap().put(k0(), v3()));

    assertGet(k0(), v0(), v3());
    assertEquals(size + 1, multimap().size());
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutTwoElements() {
    int size = getNumElements();

    List<V> values = copyToList(multimap().get(k0()));

    assertTrue(multimap().put(k0(), v1()));

      result = murmurHash64WithSeed(bytes, offset, length, K0 ^ K1 ^ K2);
    } else if (length <= 64) {
      result = hashLength33To64(bytes, offset, length);
    } else {
      result = fullFingerprint(bytes, offset, length);
    }

    long u = length >= 8 ? load64(bytes, offset) : K0;
    long v = length >= 9 ? load64(bytes, offset + length - 8) : K0;
    result = hash128to64(result + v, u);

  public void testRemoveAbsent() {
    assertFalse(multimap().remove(k0(), v1()));
    expectUnchanged();
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemovePresent() {
    assertTrue(multimap().remove(k0(), v0()));

    assertFalse(multimap().containsEntry(k0(), v0()));
    expectMissing(e0());
    assertEquals(getNumElements() - 1, multimap().size());