code: @NonNull
    public CacheStats plus(@NonNull CacheStats other) {
      return new CacheStats(
          hitCount + other.hitCount,
          missCount + other.missCount,
          loadSuccessCount + other.loadSuccessCount,
          loadFailureCount + other.loadFailureCount,
          totalLoadTime + other.totalLoadTime,
          evictionCount + other.evictionCount,
          evictionWeight + other.evictionWeight);
    }
docs: Returns a new {@code CacheStats} representing the sum of this {@code CacheStats} and
  {@code other}.
  
  @param other the statistics to add with
  @return the sum of the statistics