Connection pooling and socket errors

[didactic-drunk]

With a large number of requests I get the following error:

Unhandled exception: Error connecting to '...': Can't assign requested address (Socket::ConnectError)

Could a connection pool with persistent connections be used instead of 1 connection per request?

[jgaskins]

@didactic-drunk That's a big part of the motivation behind crystal-lang/crystal-db#131 — I want to extract the connection pool from that shard so it can be used for other network clients like this. I'm already using it in my Redis shard and my own AWS client (not yet extracted from the app it lives in). So the application I'm working on that uses Postgres, Redis, and AWS uses the same connection pool class for all 3.