# File lib/delayed/worker.rb, line 208
    def work_off(num = 100)
      success = 0
      failure = 0

      num.times do
        case reserve_and_run_one_job
        when true
          success += 1
        when false
          failure += 1
        else
          break # leave if no work could be done
        end
        break if stop? # leave if we're exiting
      end

      [success, failure]
    end