Michael Brown
272fe32529
[tls] Support stateful session resumption
Record the session ID (if any) provided by the server and attempt to
reuse it for any concurrent connections to the same server.
If multiple connections are initiated concurrently (e.g. when using
PeerDist) then defer sending the ClientHello for all but the first
connection, to allow time for the first connection to potentially
obtain a session ID (and thereby speed up the negotiation for all
remaining connections).
Signed-off-by: Michael Brown <mcb30@ipxe.org>