`PGconn` has a field `status` that (realistically) has two possible values:
`CONNECTION_OK` and `CONNECTION_BAD`. The postgres library itself sets the
status to `CONNECTION_BAD` in case there are eg communication errors. How
confident can I be that this behaviour is reflected in `db_connector`?
treeform's library seems to `assert` on it (which, imho, is bad, since it makes
connection errors unrecoverable) but I'm thinking I should call `pqstatus`
(which just wraps the postgres library's `PQstatus`) just in case