support fo connect_to

[initprism]

I know that this crates supports DNS resolve. However, the connect_to function is missing. libcurl-connect_to

curl-rs is already supporting it. see

[sagebind]

This is a good suggestion, this sounds like something that would be totally appropriate for us to support! One difference between this and dns_resolve is that we can support this on a per-request basis, whereas we're forced to limit dns_resolve to be client-wide to avoid weird behavior with concurrent requests.