D3 sumtype api

[monkyyy]

On Friday, 28 February 2025 at 01:25:29 UTC, Paul Backus wrote:
> If your match is using SumType's private interface, and it 
> breaks, that's your fault. Use the public interface if you 
> don't want breakage.

Im trying to suggest the public interface, if we were both 
working on the problem of sumtype nullable unification all the 
more reason to get some agreed on names.

I will forever use `popFront` dispite my active disgust that its 
not `pop`, given the goal of lazy making code work.