ReferenceError: $toast is not defined

I'm using Laravel mix with Vue (Node + Webpack). I've imported the library:

```
import VueIziToast from 'vue-izitoast';
import "izitoast/dist/css/iziToast.min.css";
Vue.use(VueIziToast);
```

but after trying to use `$toast` in my app it says that is not defined. Am I missing something? The code compiles correctly.