code: func (h HostPortInfo) Add(ip, protocol string, port int32) {
  	if port <= 0 {
  		return
  	}
  
  	h.sanitize(&ip, &protocol)
  
  	pp := NewProtocolPort(protocol, port)
  	if _, ok := h[ip]; !ok {
  		h[ip] = map[ProtocolPort]struct{}{
  			*pp: {},
  		}
  		return
  	}
  
  	h[ip][*pp] = struct{}{}
  }
docs: // Add adds (ip, protocol, port) to HostPortInfo