I love the Atomic ARC. Initially, I entertained the idea of having both a ref and thread-safe atomic ref. However, upon further reflection, I don't reckon it's a good idea. Numerous refs come from libraries that you can't edit. Sure, refs can influence one another, such as all refs of an atomic ref atomic as well - the "ref coloring problem". But what if you set an atomic to a local ref? Does that make it atomic too? It's overly convoluted and not worthwhile.
The solution is to use a simple arc for single threads, and when --threads:on is enabled, it should use atomic refs. The negligible speed loss is inconsequential. Look, I'm all about speed, but when you're optimizing for speed, you shift to using non ref objects, UnsafeArrays and pointers. Refs should be about convenience. I feel Nim does not have a good solution for threading right now. My CPU has 32 cores! I think Atomic ARC is one step closer to making Nim be really good at threads.
