ThreadPoolExhaustedListener 在最新版本中未发现用户配置的入口，这个功能的设计初衷我理解，是发生线程池耗尽通知给应用，目前没看到应用如何添加监听的地方。
* Thread pool core thread size
     */
    private Integer corethreads;
    /**
     * Thread pool size (fixed size)
     */
    private Integer threads;
    /**
     * IO thread pool size (fixed size)
     */
    private Integer iothreads;
    /**
     * Thread pool keepAliveTime, default unit TimeUnit.MILLISECONDS
     */
    private Integer alive;
    /**
     * Thread pool's queue length
     */
    private Integer queues;
    /**
     * Max acceptable connections
     */
    private Integer accepts;
    /**
     * Protocol codec
     */
    private String codec;
    /**
     * Serialization
     */