start method

@override Future<void> start({ required NodeId self, required String appId, })

Starts the transport, advertising self under appId.

Implementation

@override
Future<void> start({required NodeId self, required String appId}) async {
  if (_started) throw StateError('LanTransport already started');
  _started = true;
  _self = self;
  _serviceType = '_passnote-$appId._tcp';

  // 1. WebSocket server on an ephemeral port. Remote-fed input: a request
  // that fails mid-handling is dropped, never an unhandled async error.
  final server = await HttpServer.bind(InternetAddress.anyIPv4, 0);
  _wsServer = server;
  server.listen(_handleHttpRequest, onError: (Object _) {});

  // 2. Advertise this node over mDNS. A platform that refuses multicast (a
  // missing entitlement or local-network permission) must not crash the
  // app: the transport stays up without discovery — the failure mode the
  // platform-setup guide documents — and a [DiscoveryUnavailable] event
  // tells the app why no peers will appear.
  await _advertise(self, server.port);

  // 3. Browse for peers immediately and on an interval. Only the mDNS
  // query itself runs guarded (see [_discover]); dialing and socket
  // handling keep normal error propagation, like the accepting side.
  unawaited(_browse());
  _discoveryTimer =
      Timer.periodic(_discoveryInterval, (_) => unawaited(_browse()));
}