Can we set up a socket with kTLS? Can we handoff a kTLS socket between processes?

These are interesting questions. To answer them, we should extend the listening process in SERVER-114167 to upon accepting a TCP socket,
1. Negotiate a TLS session with OpenSSL
2. Use the session to establish kTLS

This should allow the echo server to send and receive encrypted messages, without even needing to link OpenSSL.