if (monitor.enterIf(isStoppable)) {
      try {
        State previous = state();
        switch (previous) {
          case NEW:
            snapshot = new StateSnapshot(TERMINATED);
            enqueueTerminatedEvent(NEW);
            break;
          case STARTING:
            snapshot = new StateSnapshot(STARTING, true, null);
            enqueueStoppingEvent(STARTING);
            doCancelStart();
            break;