fixed peer learning from first package (race condition)

app/test/transport/udp_transport_test.dart

@@ -188,6 +188,19 @@ void main() {
     transport.dispose();
   });
 
+  test(
+    'falls back to the default mLRS bridge IP when neither a host is '
+    'configured nor a gateway address is reported',
+    () async {
+      final fake = FakeMlrsNetworkController();
+      final transport = await connectWithFake(fake);
+
+      expect(transport.peerDescription, startsWith('192.168.4.55'));
+
+      transport.dispose();
+    },
+  );
+
   test('a configured host overrides the reported gateway address', () async {
     final fake = FakeMlrsNetworkController();
     final transport = await connectWithFake(
@@ -223,9 +236,17 @@ void main() {
     transport.dispose();
   });
 
-  test('send() without a known peer throws LinkConnectException', () async {
+  test('send() before the socket is open throws LinkConnectException',
+      () async {
     final fake = FakeMlrsNetworkController();
-    final transport = await connectWithFake(fake);
+    final transport = UdpTransport(
+      getHost: () async => null,
+      getPort: () async => 0,
+      getSsidPrefix: () async => 'mLRS-',
+      getRememberedSsid: () async => null,
+      rememberSsid: (_) async {},
+      networkController: fake,
+    );
 
     expect(
       () => transport.send(Uint8List.fromList([1])),
@@ -235,6 +256,22 @@ void main() {
     transport.dispose();
   });
 
+  test(
+    'send() works with the default mLRS bridge IP even before any packet '
+    'has been received',
+    () async {
+      final fake = FakeMlrsNetworkController();
+      final transport = await connectWithFake(fake);
+
+      await transport.send(Uint8List.fromList([1, 2, 3]));
+
+      expect(fake.sentPackets, hasLength(1));
+      expect(fake.sentPackets.single.host, '192.168.4.55');
+
+      transport.dispose();
+    },
+  );
+
   test('send() forwards bytes to the learned peer via the native socket',
       () async {
     final fake = FakeMlrsNetworkController();