Can calling @import url(…) from CSS to a slow remote server "hang" the output of the entire page to the screen, and in what browsers?

Question

Google Fonts

As a rule, the browser first downloads the styles, and only then displays the page on the screen.
The question is: to what extent and in what browsers does the “hanging” of the remote server indicated by the directive “ @import url('http:…'); ' in CSS - if this server does not issue an immediate error, but simply "churns" the CSS code bytes too slowly - can lead to a similar "freeze" of the browser and force the site reader to contemplate an empty window for a long time instead of an unstyled site?
The answer to this question is important, for example, to determine the usefulness of font hosting with server-side font format selection based on the analysis of the "user-agent" header - in other words, to determine the measure of usefulness and potential harmfulness of sites that are functionally similar to Google Web Fonts, but created by smaller companies that have at their disposal less developed “server farms” that can suffer painfully from the habra effect, from the slash dot effect, and simply from their own popularity.
(Since it’s not so easy to search the Internet for “@import” separately from “import”, I myself managed to find only the line on this topic “If an Dmitrijs Balcers is done to a slow-loading server, it will cause browser hangs ” in the tutorial on creating custom styles on the famous site userstyles.org - but, unfortunately, it does not indicate which browsers this problem is relevant for.)

Answer 1

Maybe it's worth simulating the situation and testing it in practice?