Boehm is not about ownership models. Boehm was _not_ recently added nor removed.
`--gc:boehm` refers to [https://en.wikipedia.org/wiki/Boehm_garbage_collector](https://en.wikipedia.org/wiki/Boehm_garbage_collector) On internet theres some articles saying is terribly slow in theory, but for some reason on Nim in actual usage is very fast, sometimes faster than Mark & Sweep. Nim can do thread with boehm.
