private IMetadataSet GetDataSet <T>()
        {
#if UNSAFE_QUERY
            return(DataSetMap[typeof(T)]);
#else
            return(DataSetMap.ContainsKey(typeof(T)) ? DataSetMap[typeof(T)] : null);
#endif
        }
 public bool HasType <T>() => DataSetMap.ContainsKey(typeof(T));