performance.getEntries() can't get failed requests.

[Handsome2734]

For example, I added '0.0.0.0 avatars2.githubusercontent.com' into /etc/hosts, then visited github.com.
After page fully loaded, I run performance.getEntriesByType('resource').filter(function(entry){return /avatars2\.githubusercontent\.com/.test(entry.name)}); in the console, I got nothing.
However in production env, sometimes it's important to know how many requests are timeout or aborted by the browser.
Hope there will be an api or some way to get that.

[igrigorik]

Please see w3c/resource-timing#12.