I am a fan of programming by contract myself, but I'm not quite sure it could be pasted onto Go's interfaces quite so simply. In the case of Heap perhaps it co

I am a fan of programming by contract myself, but I'm not quite sure it could be pasted onto Go's interfaces quite so simply. In the case of Heap perhaps it could be done in a straight forward way, but what about more generic things that have more to do with side-effects?