[deltasepsilon]

Woah, I can't believe it, I've found the discussion that linked the thing I was looking for. [1] It's called Coz, the causal profiler [2]. I've submitted this talk again, because I think it's super interesting.

[1] https://news.ycombinator.com/item?id=36366179

[2] https://www.youtube.com/watch?v=r-TLSBdHe1A