I don't like the `Option` here at all. It's a flag, and it doesn't make sense to have 3 possible states: network interfaces either support MMDS or they don't - this can be implemented either as a `bool` flag, or as an `Option<MmdsNetworkStack>`. (I'm aware that if you break the API compatibility, that will bring a lot more changes in the tests than there are in this PR :grimacing:)