ajax with cookies

Right now we are using `viewer.js` without Data Providers. If I understand correctly `viewer.js` does the XMLHttpRequests for you in this case.
The problem is we need to somehow send a cookie with the XMLHttpRequest.

I thought, oh nice, they have this thing called Data Providers with a `.get()` method, but it doesn't seem like you can specify `withCredentials`.

TL;DR
Is there a way to set `withCredentials` to `true`?

Start in viewer.js and trace how XMLHttpRequests are made when Data Providers are not used, then compare that path with the Data Providers .get() method. Determine whether withCredentials can be configured, and confirm that the completed behavior allows the required cookie to accompany the request.

Written by the indexing model from the issue text.