presto-main/src/main/java/io/prestosql/util/FinalizerService.java/FinalizerService/start
class FinalizerService:    @PostConstruct
    public synchronized void start()
    {
        if (finalizerTask != null) {
            return;
        }
        if (executor == null) {
            executor = newSingleThreadExecutor(daemonThreadsNamed("FinalizerService"));
        }
        if (executor.isShutdown()) {
            throw new IllegalStateException("Finalizer service has been destroyed");
        }
        finalizerTask = executor.submit(this::processFinalizerQueue);
    }