docs: public static int checkBackupCount(int newBackupCount, int currentAsyncBackupCount) {
          if (newBackupCount < 0) {
              throw new IllegalArgumentException("backup-count can't be smaller than 0");
          }
  
          if (currentAsyncBackupCount < 0) {
              throw new IllegalArgumentException("async-backup-count can't be smaller than 0");
          }
  
          if (newBackupCount > MAX_BACKUP_COUNT) {
              throw new IllegalArgumentException("backup-count can't be larger than than " + MAX_BACKUP_COUNT);
          }
  
          if (newBackupCount + currentAsyncBackupCount > MAX_BACKUP_COUNT) {
              throw new IllegalArgumentException("the sum of backup-count and async-backup-count can't be larger than than "
                      + MAX_BACKUP_COUNT);
          }
  
          return newBackupCount;
      }