return new SerializedForm<>(delegate());
  }

  private void readObject(ObjectInputStream stream) throws InvalidObjectException {
    throw new InvalidObjectException("Use SerializedForm");
  }

  /** Serialized form of the map, to avoid serializing the constraint. */
  private static final class SerializedForm<B extends @Nullable Object> implements Serializable {
    private final Map<Class<? extends @NonNull B>, B> backingMap;

   *
   * @return the re-serialized object
   * @throws RuntimeException if the specified object was not successfully serialized or
   *     deserialized
   */
  @CanIgnoreReturnValue
  public static <T> T reserialize(T object) {
    return Platform.reserialize(object);
  }

  /**
   * Serializes and deserializes the specified object and verifies that the re-serialized object is

  private Serialization() {}

  /**
   * Reads a count corresponding to a serialized map, multiset, or multimap. It returns the size of
   * a map serialized by {@link #writeMap(Map, ObjectOutputStream)}, the number of distinct elements
   * in a multiset serialized by {@link #writeMultiset(Multiset, ObjectOutputStream)}, or the number
   * of distinct keys in a multimap serialized by {@link #writeMultimap(Multimap,
   * ObjectOutputStream)}.
   */

  }

  @Override
  public boolean isEmpty() {
    return delegateCollection().isEmpty();
  }

  @Override
  boolean isPartialView() {
    return delegateCollection().isPartialView();
  }

  /** Serialized form that leads to the same performance as the original list. */
  @GwtIncompatible // serialization
  @J2ktIncompatible
  static class SerializedForm implements Serializable {
    final ImmutableCollection<?> collection;

  }

  @Override
  public boolean isEmpty() {
    return delegateCollection().isEmpty();
  }

  @Override
  boolean isPartialView() {
    return delegateCollection().isPartialView();
  }

  /** Serialized form that leads to the same performance as the original list. */
  @GwtIncompatible // serialization
  @J2ktIncompatible
  static class SerializedForm implements Serializable {
    final ImmutableCollection<?> collection;

 *
 * <p>This class is used only for micro-optimization. Standard {@code Future} utilities benefit from
 * this optimization, so there is no need to specialize methods to return or accept this type
 * instead of {@code ListenableFuture}.
 *
 * <p>This class is GWT-compatible.
 *
 * @since {@code com.google.guava:failureaccess:1.0}, which was added as a dependency of Guava in

    return proxyClass.isInstance(arg)
        // Equal proxy instances should mostly be instance of proxyClass
        // Under some edge cases (such as the proxy of JDK types serialized and then deserialized)
        // the proxy type may not be the same.
        // We first check isProxyClass() so that the common case of comparing with non-proxy objects
        // is efficient.

  final transient List<E> delegate;
  // This reference is used both by the custom field serializer, and by the
  // GWT compiler to infer the elements of the lists that needs to be
  // serialized.
  E element;

  SingletonImmutableList(E element) {
    this.delegate = singletonList(checkNotNull(element));
    this.element = element;
  }

  @Override
  List<E> delegateList() {
    return delegate;