pub fn spawn_async_with_pipes<P: AsRef<Path>, T: FromRawFd, U: FromRawFd, V: FromRawFd>( working_directory: P, argv: &[&Path], envp: &[&Path], flags: SpawnFlags, child_setup: Option<Box_<dyn FnOnce() + 'static>>) -> Result<(Pid, T, U, V), Error>
