win fork

https://stackoverflow.com/questions/985281/what-is-the-closest-thing-windows-has-to-fork

https://news.ycombinator.com/item?id=8449164

http://www.doublersolutions.com/docs/dce/osfdocs/htmls/develop/appdev/Appde193.htm

https://stackoverflow.com/questions/39890363/what-happens-when-a-thread-forks

https://stackoverflow.com/questions/6078712/is-it-safe-to-fork-from-within-a-thread/6079669#6079669