private static int minThreads(ContainerThreadpoolConfig config, int max, int cpus) {
        int threads;
        if (config.minThreads() > 0) threads = config.minThreads();
        else if (config.minThreads() == 0) threads = 4 * cpus;
        else threads = Math.max(MIN_THREADS_WHEN_SCALE_FACTOR, Math.abs(config.minThreads()) * cpus);
        return Math.min(threads, max);
    }
Shutdown the thread pool, give a grace period of 1 second before forcibly
shutting down all worker threads.
container-core/src/main/java/com/yahoo/container/handler/threadpool/ContainerThreadpoolImpl.java