Feature Request: Add "pg" as TLS-ALPN

In the same place that SNI is being passed to openssl during the client-initiated TLS, could we get ALPN set to "pg" by default (and perhaps an --alpn​ <proto|empty-string>​ and/or --no-alpn​) to assist in protocol routing / virtual hosting?

P.S. I'm willing to personally fund the development of these two features I've requested. It would come out of my own pocket (no investors or enterprise behind me) - but I do a variety of development for a variety of clients and I believe that these changes will indirectly end up putting enough money back in my own pocket to make it worth it over the years. I could contract a member of the core team or, if we got to a sure-fire "will accept given these conditions", I could find someone in my friend or work group to commission to make the changes.

AJ ONeal