*
     * <p>Canceling this future will attempt to cancel all the component futures.
     *
     * @return a future whose result is based on {@code combiner} (or based on the input futures
     *     passed to {@code whenAllSucceed}, if that is the method you used to create this {@code
     *     FutureCombiner}). Even if you don't care about the value of the future, you should