* @since 21.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class SpliteratorTester<E extends @Nullable Object> {
  /** Return type from "contains the following elements" assertions. */
  public interface Ordered {
    /**
     * Attests that the expected values must not just be present but must be present in the order
     * they were given.
     */
    void inOrder();
  }

    @SuppressWarnings("unchecked") // implementation is "fully variant"
    SupplierFunction<T> sf = (SupplierFunction<T>) SupplierFunctionImpl.INSTANCE;
    return sf;
  }

  private interface SupplierFunction<T extends @Nullable Object> extends Function<Supplier<T>, T> {}

  private enum SupplierFunctionImpl implements SupplierFunction<@Nullable Object> {
    INSTANCE;

  private static List<Object> subListCopy(Object[] source, int size) {
    final Object[] copy = new Object[size];
    System.arraycopy(source, 0, copy, 0, size);
    return Arrays.asList(copy);
  }

  private interface IteratorOperation {
    @Nullable Object execute(Iterator<?> iterator);
  }

  /**
   * Apply this method to both iterators and return normally only if both produce the same response.
   *

    implements Serializable {

  /**
   * Creates a new, empty multiset, sorted according to the elements' natural order. All elements
   * inserted into the multiset must implement the {@code Comparable} interface. Furthermore, all
   * such elements must be <i>mutually comparable</i>: {@code e1.compareTo(e2)} must not throw a
   * {@code ClassCastException} for any elements {@code e1} and {@code e2} in the multiset. If the

 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Preconditions {
  private Preconditions() {}

  private interface Impossible {}

  /**
   * Ensures the truth of an expression involving one or more parameters to the calling method.
   *
   * @param expression a boolean expression

  }

  @Override
  public Set<Feature<? super Set>> getImpliedFeatures() {
    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation
  public @interface Require {
    public abstract SetFeature[] value() default {};

    public abstract SetFeature[] absent() default {};
  }

  }

  @Override
  public Set<Feature<? super Multimap>> getImpliedFeatures() {
    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation
  public @interface Require {
    public abstract MultimapFeature[] value() default {};

    public abstract MultimapFeature[] absent() default {};
  }

  }

  @Override
  public Set<Feature<? super List>> getImpliedFeatures() {
    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation
  public @interface Require {
    ListFeature[] value() default {};

    ListFeature[] absent() default {};
  }

  /**
   * {@inheritDoc}
   *
   * <p>Because a {@code TreeMultimap} has unique sorted keys, this method returns a {@link
   * NavigableSet}, instead of the {@link java.util.Set} specified in the {@link Multimap}
   * interface.
   *
   * @since 14.0 (present with return type {@code SortedSet} since 2.0)
   */
  @Override
  public NavigableSet<K> keySet() {
    return (NavigableSet<K>) super.keySet();
  }

  /**

  }

  @Override
  public Set<Feature<? super Collection>> getImpliedFeatures() {
    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation
  public @interface Require {
    CollectionFeature[] value() default {};

    CollectionFeature[] absent() default {};
  }