const mwebd interface constructor

diff --git a/lib/services/mwebd_service.dart b/lib/services/mwebd_service.dart
index 3c60a9a..2462257 100644
--- a/lib/services/mwebd_service.dart
+++ b/lib/services/mwebd_service.dart
@@ -24,7 +24,11 @@ final class MwebdService {
     CryptoCurrencyNetwork.test4 => throw UnimplementedError(),
   };
 
-  final Map<CryptoCurrencyNetwork, MwebClient> _map = {};
+  final Map<
+    CryptoCurrencyNetwork,
+    ({OpaqueMwebdServer server, MwebClient client})
+  >
+  _map = {};
 
   late final StreamSubscription<TorConnectionStatusChangedEvent>
   _torStatusListener;
@@ -84,16 +88,16 @@ final class MwebdService {
           : "socks5://${proxyInfo.host.address}:${proxyInfo.port}";
       final nets = _map.keys;
       for (final net in nets) {
-        final oldClient = _map.remove(net)!;
-        await oldClient.cleanup();
-        final oldServerInfo = await mwebdServerInterface.stopServer(net);
+        final old = _map.remove(net)!;
+        await old.client.cleanup();
+        final oldServerInfo = await mwebdServerInterface.stopServer(old.server);
 
         final port = await _getRandomUnusedPort();
         if (port == null) {
           throw Exception("Could not find an unused port for mwebd");
         }
 
-        final serverPort = await mwebdServerInterface.createAndStartServer(
+        final serverData = await mwebdServerInterface.createAndStartServer(
           net,
           chain: oldServerInfo.chain,
           dataDir: oldServerInfo.dataDir,
@@ -102,7 +106,9 @@ final class MwebdService {
           serverPort: port,
         );
 
-        _map[net] = MwebClient.fromHost("127.0.0.1", serverPort);
+        final newClient = MwebClient.fromHost("127.0.0.1", serverData.port);
+
+        _map[net] = (server: serverData.server, client: newClient);
       }
     });
   }
@@ -116,10 +122,10 @@ final class MwebdService {
       }
 
       if (_map.isNotEmpty) {
-        for (final net in _map.keys) {
+        for (final old in _map.values) {
           try {
-            await _map[net]?.cleanup();
-            await mwebdServerInterface.stopServer(net);
+            await old.client.cleanup();
+            await mwebdServerInterface.stopServer(old.server);
           } catch (e, s) {
             Logging.instance.i(
               "Switching mwebd chain. Error likely expected here.",
@@ -154,7 +160,7 @@ final class MwebdService {
         proxy = "";
       }
 
-      final serverPort = await mwebdServerInterface.createAndStartServer(
+      final serverData = await mwebdServerInterface.createAndStartServer(
         net,
         chain: chain,
         dataDir: dir.path,
@@ -163,7 +169,9 @@ final class MwebdService {
         serverPort: port,
       );
 
-      _map[net] = MwebClient.fromHost("127.0.0.1", serverPort);
+      final newClient = MwebClient.fromHost("127.0.0.1", serverData.port);
+
+      _map[net] = (server: serverData.server, client: newClient);
 
       Logging.instance.i("MwebdService init($net) completed!");
     });
@@ -172,14 +180,14 @@ final class MwebdService {
   /// Get server status. Returns null if no server was initialized.
   Future<Status?> getServerStatus(CryptoCurrencyNetwork net) {
     return _updateLock.protect(() {
-      return mwebdServerInterface.getServerStatus(net);
+      return mwebdServerInterface.getServerStatus(_map[net]?.server);
     });
   }
 
   /// Get client for network. Returns null if no server was initialized.
   Future<MwebClient?> getClient(CryptoCurrencyNetwork net) async {
     return await _updateLock.protect(() async {
-      return _map[net];
+      return _map[net]?.client;
     });
   }
 
diff --git a/lib/wl_gen/interfaces/mwebd_server_interface.dart b/lib/wl_gen/interfaces/mwebd_server_interface.dart
index 08dc08f..8b597d0 100644
--- a/lib/wl_gen/interfaces/mwebd_server_interface.dart
+++ b/lib/wl_gen/interfaces/mwebd_server_interface.dart
@@ -3,7 +3,9 @@ import '../../wallets/crypto_currency/crypto_currency.dart';
 export '../generated/mwebd_server_interface_impl.dart';
 
 abstract class MwebdServerInterface {
-  Future<int> createAndStartServer(
+  const MwebdServerInterface();
+
+  Future<({OpaqueMwebdServer server, int port})> createAndStartServer(
     CryptoCurrencyNetwork net, {
     required String chain,
     required String dataDir,
@@ -13,10 +15,10 @@ abstract class MwebdServerInterface {
   });
 
   Future<({String chain, String dataDir, String peer})> stopServer(
-    CryptoCurrencyNetwork net,
+    OpaqueMwebdServer server,
   );
 
-  Future<Status?> getServerStatus(CryptoCurrencyNetwork net);
+  Future<Status?> getServerStatus(OpaqueMwebdServer? server);
 }
 
 // local copy
@@ -60,3 +62,11 @@ class Status {
     blockTime,
   );
 }
+
+final class OpaqueMwebdServer {
+  final Object _value;
+
+  const OpaqueMwebdServer(this._value);
+
+  T get<T>() => _value as T;
+}
diff --git a/tool/wl_templates/MWEBD_mwebd_server_interface_impl.template.dart b/tool/wl_templates/MWEBD_mwebd_server_interface_impl.template.dart
index bf3793e..55ba2c6 100644
--- a/tool/wl_templates/MWEBD_mwebd_server_interface_impl.template.dart
+++ b/tool/wl_templates/MWEBD_mwebd_server_interface_impl.template.dart
@@ -12,13 +12,17 @@ MwebdServerInterface _getInterface() => throw Exception("MWEBD not enabled!");
 
 //END_OFF
 //ON
-MwebdServerInterface _getInterface() => _MwebdServerInterfaceImpl();
+MwebdServerInterface _getInterface() => const _MwebdServerInterfaceImpl();
+
+extension _OpaqueMwebdServerExt on OpaqueMwebdServer {
+  MwebdServer get value => get();
+}
 
 class _MwebdServerInterfaceImpl extends MwebdServerInterface {
-  final Map<CryptoCurrencyNetwork, MwebdServer> _map = {};
+  const _MwebdServerInterfaceImpl();
 
   @override
-  Future<int> createAndStartServer(
+  Future<({OpaqueMwebdServer server, int port})> createAndStartServer(
     CryptoCurrencyNetwork net, {
     required String chain,
     required String dataDir,
@@ -26,10 +30,6 @@ class _MwebdServerInterfaceImpl extends MwebdServerInterface {
     String proxy = "",
     required int serverPort,
   }) async {
-    if (_map[net] != null) {
-      throw Exception("Server for $net already exists");
-    }
-
     final newServer = MwebdServer(
       chain: chain,
       dataDir: dataDir,
@@ -39,22 +39,26 @@ class _MwebdServerInterfaceImpl extends MwebdServerInterface {
     );
     await newServer.createServer();
     await newServer.startServer();
-    _map[net] = newServer;
-    return newServer.serverPort;
+    return (server: OpaqueMwebdServer(newServer), port: newServer.serverPort);
   }
 
   @override
   Future<({String chain, String dataDir, String peer})> stopServer(
-    CryptoCurrencyNetwork net,
+    OpaqueMwebdServer server,
   ) async {
-    final server = _map.remove(net);
-    await server!.stopServer();
-    return (chain: server.chain, dataDir: server.dataDir, peer: server.peer);
+    final actual = server.value;
+    final data = (
+      chain: actual.chain,
+      dataDir: actual.dataDir,
+      peer: actual.peer,
+    );
+    await actual.stopServer();
+    return data;
   }
 
   @override
-  Future<Status?> getServerStatus(CryptoCurrencyNetwork net) async {
-    final status = await _map[net]?.getStatus();
+  Future<Status?> getServerStatus(OpaqueMwebdServer? server) async {
+    final status = await server?.value.getStatus();
     if (status == null) return null;
 
     return Status(