Java io.reactivex.internal.schedulers.IoScheduler.CachedWorkerPool的工作原理？；

下面是一些代码片段-

CachedWorkerPool(long keepAliveTime, TimeUnit unit, ThreadFactory threadFactory) {
    this.keepAliveTime = unit != null ? unit.toNanos(keepAliveTime) : 0L;
    this.expiringWorkerQueue = new ConcurrentLinkedQueue<ThreadWorker>();
    this.allWorkers = new CompositeDisposable();
    this.threadFactory = threadFactory;

    ScheduledExecutorService evictor = null;
    Future<?> task = null;
    if (unit != null) {  
        evictor = Executors.newScheduledThreadPool(1, EVICTOR_THREAD_FACTORY);
        task = evictor.scheduleWithFixedDelay(this, this.keepAliveTime, this.keepAliveTime, TimeUnit.NANOSECONDS);
    }
    evictorService = evictor;
    evictorTask = task;
}

CachedWorkerPool（长keepAliveTime、时间单位、ThreadFactory ThreadFactory）{
this.keepAliveTime=unit！=null？unit.toNanos（keepAliveTime）：0L；
this.expiringWorkerQueue=新的ConcurrentLinkedQueue（）；
this.allWorkers=newcompositedisposable（）；
this.threadFactory=threadFactory；
ScheduledExecutorService驱逐器=null；
未来任务=null；
如果（单位！=null）{
executor=Executors.newScheduledThreadPool（1，executor\u THREAD\u工厂）；
task=exector.scheduleWithFixedDelay（this，this.keepAliveTime，this.keepAliveTime，TimeUnit.NANOSECONDS）；
}
驱逐者服务=驱逐者；
驱逐任务=任务；
}

“驱逐者服务”是为什么而设计的？

---

何时何地使用？

为什么？管理一个

调度程序.Worker

实例池，并在一段时间后不使用时将其关闭。@重写public void run（）{//清除过期的任务 executedExpiredWorkers（）；}您能告诉我什么时候触发了then run函数来执行executedExpiredWorkers函数吗，我就是无法启动。executer以

keepAliveTime

频率运行定期计时器，并调用

executedExpiredWorkers（）

。