*     remove()}, {@code set()}, and {@code add()} calls
   */
  protected void verify(List<E> elements) {}

  /** Executes the test. */
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public final void test() {
    try {
      recurse(0);
    } catch (Exception e) { // sneaky checked exception
      throw new RuntimeException(Arrays.toString(stimuli), e);

   *     remove()}, {@code set()}, and {@code add()} calls
   */
  protected void verify(List<E> elements) {}

  /** Executes the test. */
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public final void test() {
    try {
      recurse(0);
    } catch (Exception e) { // sneaky checked exception
      throw new RuntimeException(Arrays.toString(stimuli), e);

  AbstractTransformFuture(ListenableFuture<? extends I> inputFuture, F function) {
    this.inputFuture = checkNotNull(inputFuture);
    this.function = checkNotNull(function);
  }

  @Override
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public final void run() {
    @RetainedLocalRef ListenableFuture<? extends I> localInputFuture = inputFuture;
    @RetainedLocalRef F localFunction = function;

  public static DoubleStream stream(OptionalDouble optional) {
    return optional.isPresent() ? DoubleStream.of(optional.getAsDouble()) : DoubleStream.empty();
  }

  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  private static void closeAll(BaseStream<?, ?>[] toClose) {
    // If one of the streams throws an exception, continue closing the others, then throw the

  public static DoubleStream stream(OptionalDouble optional) {
    return optional.isPresent() ? DoubleStream.of(optional.getAsDouble()) : DoubleStream.empty();
  }

  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  private static void closeAll(BaseStream<?, ?>[] toClose) {
    // If one of the streams throws an exception, continue closing the others, then throw the