WsZ21Service ctor may throw

[higaski]

Frontend/lib/service/roco/ws_z21_service.dart

Lines 25 to 41 in 3bce612

	WsZ21Service(String domain) {
	_channel = WebSocketChannel.connect(Uri.parse('ws://$domain/roco/z21/'));
	_channel.ready.then(
	(_) => lanSetBroadcastFlags(
	BroadcastFlags.fromList([
	BroadcastFlag.DrivingSwitching,
	BroadcastFlag.RBus,
	BroadcastFlag.LocoNet,
	BroadcastFlag.LocoNetDetector,
	]),
	),
	);
	_stream = _channel.stream
	.asBroadcastStream()
	.cast<Uint8List>()
	.map(Z21Service.convert);
	}

.ready.then can throw here and at this point this particular Future is fire-and-forget and lives outside of Riverpod's error handling...