[PATCH] Keepalive: add new option "keepalive_ssl_respect_sni"

[geniuss99]

> From the design point of view, upstream{} blocks expect all
> connections to a peer to be equivalent.

I see your point.

One upstream block per static set of rules (connection-specific settings).

What I need is one upstream block per dynamic set of rules.
With current design this means creating as many upstream blocks as
there are sets of rules.

So if I have hundreds of such sets I will need to create hundreds of
identical upstream blocks with different names.
This is simple yet not flexible at all.

Sounds like we need new upstream module for such usecases, something
like "superupstream" :)