class Concurrent::Agent

def enqueue_await_job(latch)
  synchronize do
    if (index = ns_find_last_job_for_thread)
      job = Job.new(AWAIT_ACTION, [latch], Concurrent.global_immediate_executor,
                    Thread.current.object_id)
      ns_enqueue_job(job, index+1)
    else
      latch.count_down
      true
    end
  end
end