code: func SplitPortProto(raw string) (port string, protocol string) {
  	parts := strings.SplitN(raw, "/", 2)
  	if len(parts) == 1 {
  		return parts[0], "tcp"
  	}
  	return parts[0], parts[1]
  }
docs: // SplitPortProto splits a string in the format port/protocol, defaulting
  // protocol to "tcp" if not provided.