*
     * @param elements the {@code Iterable} to add to the {@code ImmutableMultiset}
     * @return this {@code Builder} object
     * @throws NullPointerException if {@code elements} is null or contains a null element
     */
    @CanIgnoreReturnValue
    @Override
    public Builder<E> addAll(Iterable<? extends E> elements) {
      requireNonNull(contents); // see the comment on the field

  public SampleElements<E> samples() {
    return delegate.samples();
  }

  @Override
  public E[] createArray(int length) {
    return delegate.createArray(length);
  }

  @Override
  public Iterable<E> order(List<E> insertionOrder) {
    return delegate.order(insertionOrder);
  }

import java.util.Set;
import org.jspecify.annotations.NullUnmarked;

@NullUnmarked
public final class SetsFilterHashSetTest extends AbstractFilteredSetTest<Set<Integer>> {
  @Override
  Set<Integer> createUnfiltered(Iterable<Integer> contents) {
    return newHashSet(contents);
  }

  @Override
  Set<Integer> filter(Set<Integer> elements, Predicate<? super Integer> predicate) {
    return Sets.filter(elements, predicate);
  }

  K[] createKeyArray(int length);

  V[] createValueArray(int length);

  SampleElements<K> sampleKeys();

  SampleElements<V> sampleValues();

  Collection<V> createCollection(Iterable<? extends V> values);

  K[] createKeyArray(int length);

  V[] createValueArray(int length);

  SampleElements<K> sampleKeys();

  SampleElements<V> sampleValues();

  Collection<V> createCollection(Iterable<? extends V> values);

    Integer nullInt = (Integer) null;
    Ordering<@Nullable Iterable<@Nullable Integer>> example =
        Ordering.<Integer>natural()
            .<Integer>nullsFirst()
            .<@Nullable Integer>reverse()
            .<@Nullable Integer>lexicographical()
            .reverse()
            .<Iterable<@Nullable Integer>>nullsLast();
    List<@Nullable Integer> list1 = new ArrayList<>();

    Integer nullInt = (Integer) null;
    Ordering<@Nullable Iterable<@Nullable Integer>> example =
        Ordering.<Integer>natural()
            .<Integer>nullsFirst()
            .<@Nullable Integer>reverse()
            .<@Nullable Integer>lexicographical()
            .reverse()
            .<Iterable<@Nullable Integer>>nullsLast();
    List<@Nullable Integer> list1 = new ArrayList<>();

     * @since 19.0
     */
    @CanIgnoreReturnValue
    @Override
    public Builder<K, V> putAll(Iterable<? extends Entry<? extends K, ? extends V>> entries) {
      super.putAll(entries);
      return this;
    }

    @CanIgnoreReturnValue
    @Override
    public Builder<K, V> putAll(K key, Iterable<? extends V> values) {
      super.putAll(key, values);
      return this;
    }

    assertThrows(
        IllegalArgumentException.class,
        () -> map.putInstance(this.<Integer>anyIterableType(), ImmutableList.of(1)));
  }

  private <T> TypeToken<Iterable<T>> anyIterableType() {
    return new TypeToken<Iterable<T>>() {};
  }

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

  HashMultiset(int distinctElements) {