I'd like to propose a enhancement to `at_exit`. at_exit. It would be nice if you could stop a `at_exit` at_exit handler from running in subprocesses. You can do this manually with this code: ```ruby parent = Process.pid at_exit do if parent == Process.pid # … end end ``` You can also do it by bypassing handlers: ```ruby at_exit do # … end fork do exit! end ``` But it would be nice if I could do: ```ruby at_exit(false) do # … end ``` The first approach is kind of ugly, and the second approach isn't sustainable if code outside your control can `fork(…)` fork(…) without calling `exit!`. exit!.