NioEventLoop 是一个线程的线程池

executor = new ThreadPerTaskExecutor(newDefaultThreadFactory());
​
public ThreadPerTaskExecutor(ThreadFactory threadFactory) {
    this.threadFactory = threadFactory;
}
@Override
public void execute(Runnable command) {
    threadFactory.newThread(command).start();
}

public DefaultThreadFactory(String poolName, boolean daemon, int priority, ThreadGroup threadGroup) {
    prefix = poolName + '-' + poolId.incrementAndGet() + '-';
    this.daemon = daemon;
    this.priority = priority;
    this.threadGroup = threadGroup;
}