fix: allow builds without metrics

[Arqu]

Closes n0-computer/beetle#226

[dignifiedquire]

hmm, this is a lot of code 😥

[Arqu]

hmm, this is a lot of code 😥

It is, got any better ideas?

My alternative is to make a null metrics implementation and switch on that with features. Might or might not be better but should be more contained.

[dignifiedquire]

My alternative is to make a null metrics implementation and switch on that with features.

I think that might be nicer, I am worried about things like the resolver code having cfgs all over the place.

[Arqu]

My alternative is to make a null metrics implementation and switch on that with features.

I think that might be nicer, I am worried about things like the resolver code having cfgs all over the place.

Yeah it's not pretty. And a bit tedious to annotate every call to every metrics call ever. I'll do another branch for it and see where that goes.

[Arqu]

Closing in favor of #212