/// <summary />
 public static int Count <T, TType>(this IDatastoreGrouping <TType, T> source)
 {
     throw new NotImplementedException();
 }
 /// <summary />
 public static TReturn Min <T, TType, TReturn>(this IDatastoreGrouping <TType, T> source, Func <T, TReturn> selector)
 {
     throw new NotImplementedException();
 }