关于配置中心的一点儿疑问

- [ ] I have searched the [issues](https://github.com/apache/dubbo/issues) of this repository and believe that this is not a duplicate.
- [ ] I have checked the [FAQ](https://github.com/apache/dubbo/blob/master/FAQ.md) of this repository and believe that this is not a duplicate.

### Environment

* Dubbo version: 2.7.10-SNAPSHOT
* Operating System version: xxx
* Java version: xxx

### Steps to reproduce this issue

为什么在ZookeeperDynamicConfiguration要使用CountDownLatch来进行回调？
目前出现了由于zk压力过大，虽然进程成功启动并且注册成功，但是配置中心初始化超时的场景。

Pls. provide [GitHub address] to reproduce this issue.

### Expected Result

What do you expected from the above steps？

### Actual Result

What actually happens?

If there is an exception, please attach the exception trace:

```
Just put your stack trace here!
```