code: private void stopSpinning()
      {
          if (pool.spinningCount.decrementAndGet() == 0)
              for (SEPExecutor executor : pool.executors)
                  executor.maybeSchedule();
          prevStopCheck = soleSpinnerSpinTime = 0;
      }
docs: so that any producer is safe to not spin up a worker when they see a spinning thread (invariant (1) above)