/**
     * Computes a result, or throws an exception if unable to do so.
     *
     * <p>Any objects that are passed to {@link DeferredCloser#eventuallyClose(Object, Executor)
     * closer.eventuallyClose()} will be closed when the {@link ClosingFuture} pipeline is done (but
     * not before this method completes), even if this method throws or the pipeline is cancelled.
     */