4450 requests per second seems like it would only be possible in an intranet setting where the requests resolve basically instantly. I believe browsers are restricted to 8 active XHR per domain which makes it seem even less likely you could achieve this kind of throughput on an actual website with any kind of latency at all.
Do you know if the per-domain concurrent request limit is actually a request limit, or just a socket limit? That is, does it still apply if you're making all those requests using one HTTP/2 carrier socket?
