- max_size: := 10
- min_idle: := 0
- Kept open even when idle; opened in the background, so the first borrowers need not wait.
- idle_timeout: := 10 * 60_000
- An idle connection older than this is closed (ms; negative: never).
- max_lifetime: := 30 * 60_000
- A connection is closed after this long, less up to a tenth so that a fleet started together
does not reconnect together (ms; negative: never).
- health_check_after: := 30_000
- A connection idle for longer is checked with an empty Sync before it is handed out (ms;
negative: never).
- acquire_timeout: := 30_000
- How long
acquire waits for a free connection (ms; negative: no limit).