Use AbortController when available

[tchak]

No description provided.

[dgeb]

This seems promising. AbortController's compatibility is good enough now that we should take advantage of it when available.

Sorry that #630 will require a bit of refactoring.

[tchak]

I am mostly keeping it as WIP because I need to figure out a proper way of testing it :)

[tchak]

I investigated this a bit more. It will be quite annoying to test with current fetch stubbing setup. @dgeb is there a reason we are not using pretender? It has a decent support for fetch now.

[dgeb]

@dgeb is there a reason we are not using pretender? It has a decent support for fetch now.

When I started orbit, this was not true. However, I'd be fine switching to use pretender now if you prefer.

[tchak]

I will need to investigate more. Switching to pretender will require some work and will potentially prevent us from running tests on node, but will make test some fetch options easier. It's a trade-off I am not fully convinced of yet.