In the process of working on Beast, I've been adding a lot of robust unit testing for the various classes which have been ported from VFLib. During this process I have found some pretty significant defects. I am suspicious of ThreadWithCallQueue, InterruptibleThread, ParallelFor, and ThreadGroup. I'm working on fixes, but I dont plan on backporting them into VFLib. I'm not sure how the fixes will play out. But they are definitely broken.