@Override
    public void deconstruct() {
        try {
            executor.shutdown();
            if (!executor.awaitTermination(10, TimeUnit.SECONDS)) {
                log.warning("Failed to shutdown janitor in time");
            }
        } catch (InterruptedException e) {
            log.warning("Interrupted while shutting down janitor");
            Thread.currentThread().interrupt();
        }
    }
Separate janitor threadpool for tasks that cannot be executed on the jdisc default threadpool due to risk of deadlock.
Modelled as a separate component as the underlying executor must be available across {@link JettyHttpServer} instances.

@author bjorncs
container-core/src/main/java/com/yahoo/jdisc/http/server/jetty/Janitor.java