*/
    public <V extends @Nullable Object> ClosingFuture<V> callAsync(
        AsyncCombiningCallable<V> combiningCallable, Executor executor) {
      AsyncCallable<V> asyncCallable =
          new AsyncCallable<V>() {
            @Override
            public ListenableFuture<V> call() throws Exception {
              return new Peeker(inputs).callAsync(combiningCallable, closeables);
            }

    AtomicReference<ClosingFuture.Peeker> capturedPeeker = new AtomicReference<>();
    ClosingFuture<TestCloseable> closingFuture =
        ClosingFuture.whenAllComplete(ImmutableList.of(input1, input2Failed))
            .callAsync(
                new AsyncCombiningCallable<TestCloseable>() {
                  @Override
                  public ClosingFuture<TestCloseable> call(DeferredCloser closer, Peeker peeker)

     */
    public <V extends @Nullable Object> ClosingFuture<V> callAsync(
        AsyncCombiningCallable<V> combiningCallable, Executor executor) {
      AsyncCallable<V> asyncCallable =
          new AsyncCallable<V>() {
            @Override
            public ListenableFuture<V> call() throws Exception {
              return new Peeker(inputs).callAsync(combiningCallable, closeables);
            }

     *     href="https://errorprone.info/bugpattern/FutureReturnValueIgnored">https://errorprone.info/bugpattern/FutureReturnValueIgnored</a>.
     */
    public <C extends @Nullable Object> ListenableFuture<C> callAsync(
        AsyncCallable<C> combiner, Executor executor) {
      return new CombinedFuture<>(futures, allMustSucceed, executor, combiner);
    }

    /**