* for APIs like {@link #whenAllComplete whenAllComplete(...)}{@code .}{@link
   * FutureCombiner#call(Callable, Executor) call(...)}, where it is easy to use a new input from
   * the {@code call} implementation but forget to add it to the arguments of {@code
   * whenAllComplete}.
   *

    ListenableFuture<String> unused;

    // Compiles:
    unused = whenAllComplete(futureA, futureB).call(combiner, directExecutor());

    // Does not compile:
    // unused = whenAllComplete(futures).call(combiner);

    // Workaround for the above:
    unused = whenAllComplete(asList(futures)).call(combiner, directExecutor());
  }

  @J2ktIncompatible

    ListenableFuture<String> unused;

    // Compiles:
    unused = whenAllComplete(futureA, futureB).call(combiner, directExecutor());

    // Does not compile:
    // unused = whenAllComplete(futures).call(combiner);

    // Workaround for the above:
    unused = whenAllComplete(asList(futures)).call(combiner, directExecutor());
  }

  @J2ktIncompatible

   *     the arguments, or if any has already been {@linkplain #finishToFuture() finished}
   */
  public static Combiner whenAllComplete(
      ClosingFuture<?> future1, ClosingFuture<?>... moreFutures) {
    return whenAllComplete(asList(future1, moreFutures));
  }

  /**
   * Starts specifying how to combine {@link ClosingFuture}s into a single pipeline, assuming they

    AtomicReference<ClosingFuture.Peeker> capturedPeeker = new AtomicReference<>();
    ClosingFuture<TestCloseable> closingFuture =
        ClosingFuture.whenAllComplete(ImmutableList.of(input1, input2Failed))
            .call(
                (closer, peeker) -> {
                  closer.eventuallyClose(closeable1, closingExecutor);

    AtomicReference<ClosingFuture.Peeker> capturedPeeker = new AtomicReference<>();
    ClosingFuture<TestCloseable> closingFuture =
        ClosingFuture.whenAllComplete(ImmutableList.of(input1, input2Failed))
            .call(
                (closer, peeker) -> {
                  closer.eventuallyClose(closeable1, closingExecutor);