fails:Process.detach returns a thread
fails:Process.detach reaps the child process's status automatically
fails:Process.detach produces the exit Process::Status as the thread value
fails:Process.detach sets the :pid thread-local to the PID
fails:Process.detach provides a #pid method on the returned thread which returns the PID
fails:Process.detach raises TypeError when #to_int returns non-Integer value
