MultimapBuilder.linkedHashKeys().linkedHashSetValues()::<K, V>build),
        ImmutableSetMultimap::copyOf);
  }

  static <
          T extends @Nullable Object,
          K extends @Nullable Object,
          V extends @Nullable Object,
          M extends Multimap<K, V>>
      Collector<T, ?, M> toMultimap(
          Function<? super T, ? extends K> keyFunction,

   * @throws RejectedExecutionException if the task cannot be scheduled for execution
   * @since 28.2
   */
  public static <O extends @Nullable Object> ListenableFuture<O> submit(
      Callable<O> callable, Executor executor) {
    TrustedListenableFutureTask<O> task = TrustedListenableFutureTask.create(callable);
    executor.execute(task);
    return task;
  }

  /**

   */
  // All subclasses are owned by us and we'll make sure to get the R type right, including nullness.
  @SuppressWarnings({"unchecked", "nullness"})
  @CanIgnoreReturnValue
  public final @Nullable R invoke(@Nullable T receiver, @Nullable Object... args)
      throws InvocationTargetException, IllegalAccessException {
    return (R) invokeInternal(receiver, checkNotNull(args));
  }

   */
  public static <F extends @Nullable Object, T extends @Nullable Object> Collection<T> transform(
      Collection<F> fromCollection, Function<? super F, T> function) {
    return new TransformedCollection<>(fromCollection, function);
  }

  private static final class TransformedCollection<
          F extends @Nullable Object, T extends @Nullable Object>
      extends AbstractCollection<T> {

  public VerifyException(@Nullable String message) {
    super(message);
  }

  /**
   * Constructs a {@code VerifyException} with the cause {@code cause} and a message that is {@code
   * null} if {@code cause} is null, and {@code cause.toString()} otherwise.
   *
   * @since 19.0
   */
  public VerifyException(@Nullable Throwable cause) {
    super(cause);
  }

  /**

                mergeFunction),
        (s1, s2) -> s1.combine(s2, mergeFunction),
        state -> state.toTable());
  }

  static <
          T extends @Nullable Object,
          R extends @Nullable Object,
          C extends @Nullable Object,
          V,
          I extends Table<R, C, V>>
      Collector<T, ?, I> toTable(
          Function<? super T, ? extends R> rowFunction,

   *
   * @since 33.2.0 (available since 22.0 in guava-jre)
   */
  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  public static <T extends @Nullable Object, E extends @Nullable Object, M extends Multiset<E>>
      Collector<T, ?, M> toMultiset(
          Function<? super T, E> elementFunction,
          ToIntFunction<? super T> countFunction,
          Supplier<M> multisetSupplier) {

   *
   * <p>To collect to an {@link ImmutableMultiset}, use {@link
   * ImmutableMultiset#toImmutableMultiset}.
   *
   * @since 22.0
   */
  public static <T extends @Nullable Object, E extends @Nullable Object, M extends Multiset<E>>
      Collector<T, ?, M> toMultiset(
          Function<? super T, E> elementFunction,
          ToIntFunction<? super T> countFunction,
          Supplier<M> multisetSupplier) {

  }

  private static final ImmutableSet<String> NULLABLE_ANNOTATION_SIMPLE_NAMES =
      ImmutableSet.of("CheckForNull", "Nullable", "NullableDecl", "NullableType");

  static boolean isNullable(Invokable<?, ?> invokable) {
    return NULLNESS_ANNOTATION_READER.isNullable(invokable);
  }

  static boolean isNullable(Parameter param) {

  }

  @Override
  public @Nullable E lower(E element) {
    return forward.higher(element);
  }

  @Override
  public @Nullable E floor(E element) {
    return forward.ceiling(element);
  }

  @Override
  public @Nullable E ceiling(E element) {
    return forward.floor(element);
  }

  @Override
  public @Nullable E higher(E element) {
    return forward.lower(element);
  }