#  多线程工具类
**类名：** `ThreadUtil`

## sleep
```java
/**
 * Thread sleep
 *
 * @param millis 时长
 */
ThreadUtil.sleep(long millis);
```

## sleep
```java
/**
 * Thread sleep
 *
 * @param timeUnit TimeUnit
 * @param timeout  timeout
 */
ThreadUtil.sleep(TimeUnit timeUnit, long timeout);
```