@gao-artur What do you think? It currently loads both protocol implementations but only initializes the one its configured to use. I could make it only load the one it needs, but at that point maybe two different cshtml files would be better -- but that's more maintenance, and I'd prefer to just have a single cshtml file to manage. I found the js code somewhere, changed it quite a bit, modified it so that non-subscription requests will use the regular fetcher (which supports headers) and stuff. Everything seems to work like it should -- (actually it works better than before, since now the stop button works to unsubscribe).

I'm sorry, but I'm a 100% C# backend rat, and I have zero knowledge of frontend and JS (I've been trying to avoid touching them my whole career).