code: func Chroot(rootfs string) error {
  	if err := syscall.Chroot(rootfs); err != nil {
  		return errors.Wrapf(err, "unable to chroot to %s", rootfs)
  	}
  	root := filepath.FromSlash("/")
  	if err := os.Chdir(root); err != nil {
  		return errors.Wrapf(err, "unable to chdir to %s", root)
  	}
  	return nil
  }
docs: // Chroot chroot()s to the new path.
  // NB: All file paths after this call are effectively relative to
  // `rootfs`