In addition to this, with SPDY around, these first milliseconds are becoming even more important. Since SPDY requires some sort of negotiation between server and client to agree they both support the protocol, this creates a problem for the first request: how do you know a server supports SPDY without having seen a response from said server? Note that the regular HTTP Accept negotiation is not enough since the browser should already pipeline multiple requests before having seen a response.

Since the designers of SPDY also figured security is important, they made use of TLS' protocol negotiation feature: they actually announce themselves as a TLS protocol in these first milliseconds of a HTTPS connection. Brilliant.

For more information, see: http://www.chromium.org/spdy/spdy-protocol/spdy-protocol-dra...