code: public CacheStats plus(CacheStats other) {
      return new CacheStats(
          hitCount + other.hitCount,
          missCount + other.missCount,
          loadSuccessCount + other.loadSuccessCount,
          loadExceptionCount + other.loadExceptionCount,
          totalLoadTime + other.totalLoadTime,
          evictionCount + other.evictionCount);
    }
docs: Returns a new {@code CacheStats} representing the sum of this {@code CacheStats} and {@code
  other}.
  
  @since 11.0