In the linux IPTables firewall, this concept is referred to as "rate-limiting". Other possible adjectives could be "metered", "regulated", "throttled" or "periodic". I like the latter a bit more than the others.

Stealing from various games, the notion of a "cooldown timer" might also fit.

I'd think hard about a descriptive leading noun for the namespace. I don't like "Sub" as this isn't really applying to subroutines. It's more of a "Timer" or a "Constraint" when used as you did in the original article.