// lib/services/gnss/gnss_connection.dart import 'gnss_device_service.dart'; enum GnssConnectionState { disconnected, connecting, connected, error } abstract class GnssConnection { GnssConnectionType get type; /// NMEA sorok stream-je — mindkét implementáció ezt adja Stream get nmeaLines; /// Kapcsolat állapota Stream get connectionState; Future connect(String address); Future disconnect(); void dispose(); }