TLS 1.2 vs TLS 1.3

tls 1.2: 4 rtt

tls 1.3 rtt

tls 1.3 in detail

tls 1.3 wireshark

tls 1.3 0rtt rfc

rtt computation

Remark

If gap between TCP handshake and TLS handshake is extremely long, client connection could be dropped by server