Notably, this adds the new pidfd_spawn, pidfd_spawp, and pidfd_getpid functions, which should fix the PID race problem, as discussed here: <https://github.com/o

Notably, this adds the new pidfd_spawn, pidfd_spawp, and pidfd_getpid functions, which should fix the PID race problem, as discussed here: <https://github.com/oconnor663/duct.py/blob/master/gotchas.md#killing-grandchild-processes https://github.com/oconnor663/duct.py/blob/master/gotchas.md...>