When does "resolved" variable become true?

It seems that `resolved` variable in `setup-dev-server.js` is always false, when does it become true?

```
if (!resolved) resolve()
```
https://github.com/vuejs/vue-hackernews-2.0/blob/5e848096bdfc3d044ed04a019a2e1c3a3a87463d/build/setup-dev-server.js#L13

Thank you.