maybe this is just adding noise, but in case it's a helpful data point: [https://gist.github.com/brentp/dabc239aad992ccc9bc12ccb20451951](https://gist.github.com/brentp/dabc239aad992ccc9bc12ccb20451951)
with nim cpp -d:dodefer -d:release -d:danger with and without --gc:arc and the code runs about 2x slower with arc. with nim c arc is still slower, but much less of a percentage as the defers are slower.
