RFC3339.

This is default notation in dns3l.

Some providers like Infoblox don't want the dot despite being a FQDN...

To be used by "defer", rollback, only log error if the error is not that the transaction has already been committed.

this would be nice in the errors lib...

Returns a cached value for a specified amount of time (timeout)Concurrent requests for the cached value are blocked, later requestsare supplied with the cached value retrieved from earlier requests.