import java.util.Collections;
import java.util.Set;

/**
 * GWT emulation of {@link RegularImmutableSet}.
 *
 * @author Hayward Chan
 */
final class RegularImmutableSet<E> extends ForwardingImmutableSet<E> {
  static final RegularImmutableSet<Object> EMPTY =
      new RegularImmutableSet<Object>(Collections.emptySet());

  RegularImmutableSet(Set<E> delegate) {
    super(delegate);
  }

 */
@GwtCompatible
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class RegularImmutableSet<E> extends ImmutableSet.CachingAsList<E> {
  private static final Object[] EMPTY_ARRAY = new Object[0];
  static final RegularImmutableSet<Object> EMPTY =
      new RegularImmutableSet<>(EMPTY_ARRAY, 0, EMPTY_ARRAY, 0);

  private final transient Object[] elements;
  private final transient int hashCode;

  }

  @GwtIncompatible // RegularImmutableSet.table not in emulation
  private void verifyTableSize(int inputSize, int setSize, int tableSize) {
    Builder<Integer> builder = ImmutableSet.builder();
    for (int i = 0; i < inputSize; i++) {
      builder.add(i % setSize);
    }
    ImmutableSet<Integer> set = builder.build();
    assertTrue(set instanceof RegularImmutableSet);
    assertEquals(

   */
  @SuppressWarnings({"unchecked"}) // fully variant implementation (never actually produces any Es)
  public static <E> ImmutableSet<E> of() {
    return (ImmutableSet<E>) RegularImmutableSet.EMPTY;
  }

  /**
   * Returns an immutable set containing the given element. Preferred over {@link
   * Collections#singleton} for code consistency, {@code null} rejection, and because the return