Reopen #618, it is a valid feature request

[kaspar-p]

I second the use-case mentioned in https://github.com/pinojs/pino/issues/618, and think it should be reopened. Practically, it is extremely useful to know when something that's meant to exist does not exist, and not logging that fact is harmful to the usefulness of pino. It is technically correct, the worst kind.

[jsumners]

How is this not solvable with a data property and a custom serializer?

[kaspar-p]

Maybe it is :). Could you write a quick example of how I would do something like that? Might be useful for the future when folks Google a similar thing.

[jsumners]

Please refer to our documentation.