I have an `NSURL` that looks like this when printed to 
*console*:

```
<AVURLAsset: 0x170232800, URL = assets-library://asset/asset.MOV?id=426C5913-86CF-4476-2DB6-6A9AAC626AF4&ext=MOV>

```

What is the proper way to get to the id portion of this URL? Goal is to have a string with `426C5913-86CF-4476-2DB6-6A9AAC626AF4`.