I’m a browser “with the latest in header compression”, fetching a web page. I race a TCP-based ALPN run against an HTTPS record lookup (Chromium’s behavior). Either the HTTP/2 ALPN wins the race, or the HTTPS DNS record does not exist. Both are, and will remain, common scenarios. So I fetch the page over HTTP/2. This is the initial request; dynamic HPACK hasn’t kicked in. I download a 1.56kb HTTP response header:
