If a resolved address sets the port number to something besides `0`, and the port isn't otherwise explicitly asked for, the `HttpConnector` will now use that port. This allows custom resolvers that might lookup SRVB or HTTPSrr records that include a port number.

cc seanmonstar/reqwest#2413

…150)

The legacy pool client will in certain circumstances try other connections if it it notices an error just as it's trying to send a request. There is also some code that prevents retrying forever, such as if it is a new connection, since it likely won't ever work then.

However, there was a bug that this fixes, where if a new connection was successfully created, but _then_ errored when trying to send the request, it would consider retrying that. This could end up in a loop if the server accepts and then errors all connections.

The fix is to re-introduce tracking whether this connection has been successfully used once all the way through, "reused", and if it hasn't, abort any retrying.