code: func NetworkSetNsFd(iface *net.Interface, fd int) error {
  	data := uint32Attr(IFLA_NET_NS_FD, uint32(fd))
  	return networkSetNsAction(iface, data)
  }
docs: // Move a particular network interface to a particular mounted
  // network namespace specified by file descriptor.
  // This is idential to running: ip link set dev $name netns $fd