Method schedule

src/main/java/org/microhttp/Scheduler.java:35–39

(Runnable task, Duration duration)

    }

    Cancellable schedule(Runnable task, Duration duration) {
        Task t = new Task(task, clock.nanoTime() + duration.toNanos(), counter++);
        tasks.add(t);
        return t;
    }

    List<Runnable> expired() {
        long time = clock.nanoTime();