The 'secureConnection' event is emitted after the handshaking process for a
new connection has successfully completed. The listener callback is passed a
single argument when called:
tlsSocket{tls.TLSSocket} The established TLS socket.
The tlsSocket.authorized property is a boolean indicating whether the
client has been verified by one of the supplied Certificate Authorities for the
server. If tlsSocket.authorized is false, then socket.authorizationError
is set to describe how authorization failed. Depending on the settings
of the TLS server, unauthorized connections may still be accepted.
The tlsSocket.alpnProtocol property is a string that contains the selected
ALPN protocol. When ALPN has no selected protocol, tlsSocket.alpnProtocol
equals false.
The tlsSocket.servername property is a string containing the server name
requested via SNI.
