Stats need to mark up which members are required

[alvestrand]

Some fields are needed for the stats to make any sense at all. Others may or may not be present, depending on the state of the connection or the quality of the implementation.

Those that are absolutely necessary should be marked up with "required" in the IDL.

[alvestrand]

This is entirely orthogonal to the question of whether they're mandatory-to-implement.

[aboba]

@alvestrand Can we get a PR to close this issue since it is blocking issuance of the CR?

[alvestrand]

I think we can safely remove the CR-blocker label. Doing this at a later stage is not a breaking change, it's just improved documentation.