Are you talking about within the web interface? If so, then the answer is most likely no, at least not in a consistently usable format. I'll address the loading of users, but most of the internal workings of Canvas are not exposed to the user (there are a few exceptions).
The good news is that information downloaded is usually used to alter the display in some way or another and you might be able to use this to tell when the information has been downloaded.
I have used mutation observers to watch for the DOM to change and then I know that it has loaded the information. You have to be careful, though. New development is happening with ReactJS, though, and that is making it harder to do this kind of watching.
Thankfully, the People page (roster) hasn't switched over, yet. I wrote code that would allow people to sort the roster by clicking at the top of any column. It watches for when new data is appended to the list of users.
Canvas does things differently for different locations. What they do on the People page is not what they do on other pages that load lists of users. That means that a solution that works in one place may not work in another and you'll have to customize things for the particular situation you're in.
Since the information downloaded by Canvas isn't available externally, you can only use the information that they exposed on the web page unless you make the same API calls and re-download the same information. Canvas normally tells it not to cache the results, so it takes longer than it would if you could just retrieve the information from the browser's memory or disk cache.
Finally, if you are self-hosting, you can add in whatever you want and wherever you want it, so much more is possible.
Thanks for your in depth reply.
A column in the users table (frontend) should be removed once the users has
consideration I'll try to achieve this with mutation observers.
On Sun, Feb 10, 2019 at 8:29 PM email@example.com <firstname.lastname@example.org>
Not sure if you're talking about the Roster page for regular users or the Admin users page, but here are a couple of links to scripts I've written to manipulate those types of pages with MutationObservers. Hope it helps.
Retrieving data ...