`val kill : t ‑> unit`

kills `t`, which aborts all enqueued jobs that haven't started and all jobs enqueued in the future. If `t` has already been killed, then calling `kill t` has no effect. Note that kill does not affect currently running jobs in any way.

`val is_dead : t ‑> bool`

`is_dead t` returns `true` if `t` was killed, either by `kill` or by an unhandled exception in a job.

`val cost_of_jobs_waiting_to_start : t ‑> int`

returns the total cost of all jobs that have been enqueued but have not yet started.

`val to_jane_limiter : t ‑> Core_kernel.Limiter.t`

returns the underlying limiter. It is an error to do anything with the limiter that isn't a read-only operation.