kind of working!

lib/controllers/client_controller.dart

@@ -37,21 +37,25 @@ class ClientController extends Notifier<int> {
 
     GomuksStart(
       handle,
-      Pointer.fromFunction<
-        Void Function(Pointer<Char>, Int64, GomuksBorrowedBuffer)
-      >(gomuksCallback),
+      NativeCallable<
+            Void Function(Pointer<Char>, Int64, GomuksBorrowedBuffer)
+          >.listener(gomuksCallback)
+          .nativeFunction,
     );
 
     return handle;
   }
 
   Map<String, dynamic> sendCommand(String command, Map<String, dynamic> data) {
+    final bufferPointer = data.toGomuksBufferPtr();
     final response = GomuksSubmitCommand(
       state,
       command.toNativeUtf8().cast<Char>(),
-      data.toGomuksBuffer(),
+      bufferPointer.ref,
     );
 
+    calloc.free(bufferPointer);
+
     return response.buf.toJson();
   }
 

lib/helpers/extensions/gomuks_buffer.dart

@@ -31,26 +31,27 @@ extension GomuksOwnedBufferToJson on GomuksOwnedBuffer {
   Map<String, dynamic> toJson() {
     final bytes = toBytes();
     if (bytes.isEmpty) return {};
-    return jsonDecode(utf8.decode(bytes));
+    final json = jsonDecode(utf8.decode(bytes));
+
+    if (json is Map<String, dynamic>?) return json ?? {};
+    throw json;
   }
 }
 
 extension JsonToGomuksBuffer on Map<String, dynamic> {
-  GomuksBorrowedBuffer toGomuksBuffer() {
+  Pointer<GomuksBorrowedBuffer> toGomuksBufferPtr() {
     final jsonString = json.encode(this);
     final bytes = utf8.encode(jsonString);
 
     final dataPtr = calloc<Uint8>(bytes.length);
     dataPtr.asTypedList(bytes.length).setAll(0, bytes);
 
-    final bufPtr = calloc<GomuksBorrowedBuffer>();
-    bufPtr.ref.base = dataPtr;
-    bufPtr.ref.length = bytes.length;
+    final ptr = calloc<GomuksBorrowedBuffer>();
 
-    final bufByValue = bufPtr.ref;
+    ptr.ref
+      ..base = dataPtr
+      ..length = bytes.length;
 
-    calloc.free(bufPtr);
-
-    return bufByValue;
+    return ptr;
   }
 }

lib/main.dart

@@ -97,17 +97,19 @@ class App extends ConsumerWidget {
         builder: (context) => ref
             .watch(SharedPrefsController.provider)
             .betterWhen(
-              data: (_) {
-                final response = ref
-                    .watch(ClientController.provider.notifier)
-                    .sendCommand("login", {
-                      "homeserver_url": "federated.nexus",
-                      "username": "quadradical",
-                      "password": "Quadmarad1!",
-                    });
-
-                return Text(response.toString());
-              },
+              data: (_) => ElevatedButton(
+                onPressed: () async {
+                  final response = ref
+                      .watch(ClientController.provider.notifier)
+                      .sendCommand("login", {
+                        "homeserver_url": "https://matrix.federated.nexus",
+                        "username": "quadradical",
+                        "password": "Quadfnrad1!",
+                      });
+                  print(response);
+                },
+                child: Text("foo"),
+              ),
               // .betterWhen(
               //   data: (client) =>
               //       client.accessToken == null ? LoginPage() : ChatPage(),