* @return a set of entries representing the data of this multiset
   */
  Set<Entry<E>> entrySet();

  /**
   * An unmodifiable element-count pair for a multiset. The {@link Multiset#entrySet} method returns
   * a view of the multiset whose elements are of this class. A multiset implementation may return
   * Entry instances that are either live "read-through" views to the Multiset, or immutable

   * <p>Results are undefined if {@code multiset1} and {@code multiset2} are based on different
   * equivalence relations (as {@code HashMultiset} and {@code TreeMultiset} are).
   *
   * @since 14.0
   */
  public static <E extends @Nullable Object> Multiset<E> union(
      final Multiset<? extends E> multiset1, final Multiset<? extends E> multiset2) {
    checkNotNull(multiset1);
    checkNotNull(multiset2);

      @Override
      protected Multiset<String> create(String[] elements) {
        Multiset<String> multiset1 = LinkedHashMultiset.create();
        Multiset<String> multiset2 = LinkedHashMultiset.create();
        multiset1.add("equalIn1");
        multiset1.add("fewerIn1");
        multiset2.add("equalIn1");
        multiset2.add("fewerIn1", 3);
        multiset2.add("onlyIn2", 2);
        for (int i = 0; i < elements.length; i++) {

      @Override
      protected Multiset<String> create(String[] elements) {
        Multiset<String> multiset1 = LinkedHashMultiset.create();
        Multiset<String> multiset2 = LinkedHashMultiset.create();
        multiset1.add("equalIn1");
        multiset1.add("fewerIn1");
        multiset2.add("equalIn1");
        multiset2.add("fewerIn1", 3);
        multiset2.add("onlyIn2", 2);
        for (int i = 0; i < elements.length; i++) {

    assertThat(multiset).isEmpty();
  }

  public void testRemoveOccurrencesIterableEmpty() {
    Multiset<String> multiset = HashMultiset.create();
    Iterable<String> toRemove = Arrays.asList("a", "b", "a");
    assertFalse(Multisets.removeOccurrences(multiset, toRemove));
    assertTrue(multiset.isEmpty());
  }

  public void testRemoveOccurrencesMultisetEmpty() {

      Multiset<E> multiset, ObjectOutputStream stream) throws IOException {
    int entryCount = multiset.entrySet().size();
    stream.writeInt(entryCount);
    for (Multiset.Entry<E> entry : multiset.entrySet()) {
      stream.writeObject(entry.getElement());
      stream.writeInt(entry.getCount());
    }
  }

  /**

    assertThat(multiset).isEmpty();
  }

  public void testRemoveOccurrencesIterableEmpty() {
    Multiset<String> multiset = HashMultiset.create();
    Iterable<String> toRemove = Arrays.asList("a", "b", "a");
    assertFalse(Multisets.removeOccurrences(multiset, toRemove));
    assertTrue(multiset.isEmpty());
  }

  public void testRemoveOccurrencesMultisetEmpty() {

    Multiset<String> multiset = HashMultiset.create(50);
    multiset.add("foo", 2);
    multiset.add("bar");
    assertEquals(3, multiset.size());
    assertEquals(2, multiset.count("foo"));
  }

  public void testCreateFromIterable() {
    Multiset<String> multiset = HashMultiset.create(Arrays.asList("foo", "bar", "foo"));
    assertEquals(3, multiset.size());
    assertEquals(2, multiset.count("foo"));
  }

  @J2ktIncompatible

        () -> TreeMultiset.create(comparator),
        (multiset, t) ->
            multiset.add(checkNotNull(elementFunction.apply(t)), countFunction.applyAsInt(t)),
        (multiset1, multiset2) -> {
          multiset1.addAll(multiset2);
          return multiset1;
        },
        (Multiset<E> multiset) -> copyOfSortedEntries(comparator, multiset.entrySet()));
  }

  /**

   *
   * @param elements the elements that the multiset should contain
   */
  public static <E> ConcurrentHashMultiset<E> create(Iterable<? extends E> elements) {
    ConcurrentHashMultiset<E> multiset = ConcurrentHashMultiset.create();
    Iterables.addAll(multiset, elements);
    return multiset;
  }

  /**