const ANY_KIND: [MatchKind; 3];Expand description
Every kind a rule that names none of them may claim.
All three, and the list is read only for a matcher whose
Matcher::stream_kind is None: such a rule is refused for a key only
when no kind carries it. Leaving MatchKind::Datagram out of the list
would refuse a rule keyed on something only a datagram carries, and
including a kind that carried nothing would admit a rule that claims nothing
— which is why the list is the answer to what could this rule claim rather
than a restatement of the enum.