code: func (h *Handle) FilterDel(filter Filter) error {
  	req := h.newNetlinkRequest(unix.RTM_DELTFILTER, unix.NLM_F_ACK)
  	base := filter.Attrs()
  	msg := &nl.TcMsg{
  		Family:  nl.FAMILY_ALL,
  		Ifindex: int32(base.LinkIndex),
  		Handle:  base.Handle,
  		Parent:  base.Parent,
  		Info:    MakeHandle(base.Priority, nl.Swap16(base.Protocol)),
  	}
  	req.AddData(msg)
  
  	_, err := req.Execute(unix.NETLINK_ROUTE, 0)
  	return err
  }
docs: // FilterDel will delete a filter from the system.
  // Equivalent to: `tc filter del $filter`