We use detection idiom to force use of a toString member, a toString nonmember, etc... in some order.
There should be a way for user-defined types to provide an explicit method of log-stringification, as toString might not be appropriate.
It is a bad fit for DatabaseName, for example, at least during the transition to tenantId-augmented DatabaseNames.

Requires a relatively simple extension to the detection logic in logv2/attribute_storage.h