FillableEntry
      (ctor) FillableEntry( Type type )
      (ctor) FillableEntry( Type[] types )
      (ctor) FillableEntry( int weight, Type type )
      (ctor) FillableEntry( int weight, Type[] types )
      (ctor) FillableEntry( int weight, Type[] types, int offset, int count )
      Type[] Types( get; )
      int Weight( get; )
      virtual Item Construct()