code: func (h *Handle) RouteAdd(route *Route) error {
  	flags := unix.NLM_F_CREATE | unix.NLM_F_EXCL | unix.NLM_F_ACK
  	req := h.newNetlinkRequest(unix.RTM_NEWROUTE, flags)
  	return h.routeHandle(route, req, nl.NewRtMsg())
  }
docs: // RouteAdd will add a route to the system.
  // Equivalent to: `ip route add $route`