if err := unix.Tcsetpgrp(ptyFD, pgrp); err != nil {
			return fmt.Errorf("error setting tty process group: %w", err)
		}

		// Give the kernel time to potentially wake readers and have
		// them return EINTR (darwin does this).
		time.Sleep(pause)

		// Give TTY back.
		pid := int32(cmd.Process.Pid) // assume that pid_t is int32
		if err := unix.Tcsetpgrp(ptyFD, pid); err != nil {