The size of the headers response is not the issue. It's the latency of going and getting each one, and remember web browsers typically have a limited concurrenc

The size of the headers response is not the issue. It's the latency of going and getting each one, and remember web browsers typically have a limited concurrency to any one domain. You're not going to be firing off a big batch of requests in parallel and getting the responses a second later, you're going to have three or so worker processes chewing through 30 requests each in serial. The situation becomes even worse with TLS, in which the handshake is even more of a time sink. Too many requests on an https page is absolute death for performance! This technique could really help that. Pipelining would certainly help, though, if and when it finally "arrives".