// This means that the manager is currently healthy. N.B. If other threads call isHealthy
          // they are not guaranteed to get 'true', because any service could fail right now.
          enqueueHealthyEvent();
        } else if (states.count(TERMINATED) + states.count(FAILED) == numberOfServices) {
          enqueueStoppedEvent();
        }
      } finally {
        monitor.leave();