COSequence 这个类移除了吗？？还是说是自己封装的？

请问下`COSequence` 这个类是自己封装的吗？
内部是使用`COCoroutine` 生成器去实现批量下载的吗？
而且demo 中 使用
```objc
COCoroutine *co1 = xx
[co1 next]
```
next 方法no found

Start by locating the demo references to COSequence and COCoroutine and checking the repository's Objective-C examples for the documented way to advance a coroutine. Confirm whether COSequence is still part of the API and whether next is available; done means the demo and API documentation agree.

Written by the indexing model from the issue text.