Environment
Dubbo version: master
Step to reproduce this issue

```java
public boolean isAllowable() {
        long now = System.currentTimeMillis();
        if (now > lastResetTime + interval) {
            token.set(rate);
            lastResetTime = now;
        }

        int value = token.get();
        boolean flag = false;
        while (value > 0 && !flag) {
            flag = token.compareAndSet(value, value - 1);
            value = token.get();
        }

        return flag;
    }
```

Expected Result
lastResetTime 共享变量是否有内存可见性问题

```java
 if (now > lastResetTime + interval) {
            token.set(rate);
            lastResetTime = now;
        }
```

有并发问题吗？

private String name;
    private long lastResetTime;
    private long interval;
    private AtomicInteger token;
    private int rate;
    StatItem(String name, int rate, long interval) {
        this.name = name;
        this.rate = rate;
        this.interval = interval;
        this.lastResetTime = System.currentTimeMillis();
        this.token = new AtomicInteger(rate);
    }
    public boolean isAllowable() {
        long now = System.currentTimeMillis();
        if (now > lastResetTime + interval) {