initialized 未被触发。

```
var iSliderObj = new iSlider(option);
iSliderObj .on('initialized',callback); //--- 不会被触发。
```

版本2.1.7
收集器还没装载initialized到，initialized就已经执行过了。

Start by reproducing the constructor and listener sequence shown in the issue on version 2.1.7, then trace where initialization dispatches the `initialized` event and where event listeners are registered. Confirm the expected behavior with a focused reproduction; done means the documented listener sequence reliably receives the event.

Written by the indexing model from the issue text.