while this type of error is avoided when doing HEv2, the IPs remain
in the cache; this means that, one the same host is reached, the
IPs are loaded onto the same socket, and if the issue is IPv6
connectivity, it'll break outside of the HEv2 flow.
this error is now protected inside the connect block, so that other
IPs in the list can be tried after; the IP is then evicted from the
cachee.
HEv2 related regression test is disabled in CI, as it's currently
reliable in Gitlab CI, which allows to resolve the IPv6 address,
but does not allow connecting to it
Options become a bunch of session and connection level parameters, and requests do not need to maintain a separate Options object when they contain a body anymore, instead, objects is shared with the session, while request-only parameters get passed downwards to the request and its body. This reduces allocations of Options, currently the heaviest object to manage.
when closed, connections are now placed in a place called eden_connections; whenever a connection is matched for, after checking the live connections and finding none, a match is looked in eden connections; the match is accepted **if** the IP is considered fresh (the input is validated in the cache, or input was an ip or in /etc/hosts, or it's an external socket) and, if a TLS connection, the stored TLS session did not expire; if these conditions do not match, the connection is dropped from the eden and a new connection will started instead; this will therefore allow reusing ruby objects, reusing TLS sessions, and still respect the DNs cache
