Allow to use something different than time.Now when generating uuids that have a time component

[satazor]

Allow to use something different than time.Now when generating uuids that have a time component.

This is useful for:

• Tests
• In rare cases where you want to encode a timestamp different than the current time in the id, such as an expiration date.

The package at https://github.com/gofrs/uuid seems to have this functionality, see https://pkg.go.dev/github.com/gofrs/uuid/v5#WithEpochFunc. I would love to have something similar.

[it512]

If you have special requirements, please use uuidv8