> Using TLS adds latency, because of the tcp handshake required TCP Fast Open gets rid of the TCP handshake latency, but even with TLS session ids-or-tickets t

> Using TLS adds latency, because of the tcp handshake required TCP Fast Open gets rid of the TCP handshake latency, but even with TLS session ids-or-tickets there is still a round-trip for ServerHello — presumably because the standardization bodies don't trust that the client is ever capable of avoiding nonce reuse or generating a secure random number. Keeping the TCP+TLS connection alive might be feasible but you will either have to spend a lot of energy transmitting frequent keep-alive packets or run into problems on IPv4 if the network provider discards NAT mappings faster than your send interval. Unfortunately the adoption of both RFCs is really poor, with TCP Fast Open not working with Chrome on Linux (I have it set to enable in developer settings, and it does work in Firefox) and nginx still not supporting proper session ticket key rollover.