A minimum timing of an individual task is not a useful rate limit. I could schedule a bunch of tasks to happen far into the future but all at once for example.

A minimum timing of an individual task is not a useful rate limit. I could schedule a bunch of tasks to happen far into the future but all at once for example. Rate limits are implemented with e.g., token buckets which fill to a limit at a fixed rate. Timed tasks would then on run try to take a token, and if none is present wait for one. This would then be dutifully enforced regardless of the current state of scheduled tasks. Only consideration for the timer itself would be to always add random jitter to avoid having peak loads coalesce.