UI Events load event status code

Hi,

Is there a reason why status code of loaded resource is not exposed to
`load` event? (https://www.w3.org/TR/DOM-Level-3-Events/#event-type-load)

I think, it could be very useful to have it, for example in
`UIEvent.detail`.

The use-case I found is with dynamically created `<link>`s (style sheets/
HTML imports). With status code given we could control behavior for 204,
205 etc.

Best Regards,
Tomek Wytrębowicz
https://github.com/tomalec
https://twitter.com/tomalecpl