Those collections are more like copy-on-write than actual immutable. System.Collections.Frozen is the real thing.
Isn't Frozen something you do to a set or dictionary to say, I'm not going to add any more values, please give me a version of this which is optimized for lookup only?
Isn't Frozen something you do to a set or dictionary to say, I'm not going to add any more values, please give me a version of this which is optimized for lookup only?