opt.: linux/win window size & server reconnect

lib/data/model/app/rebuild.dart

@@ -0,0 +1,27 @@
+import 'package:flutter/foundation.dart';
+
+// ignore: prefer_void_to_null
+class RebuildNode implements ValueListenable<Null> {
+  final List<VoidCallback> _listeners = [];
+
+  RebuildNode();
+
+  @override
+  void addListener(VoidCallback listener) {
+    _listeners.add(listener);
+  }
+
+  @override
+  void removeListener(VoidCallback listener) {
+    _listeners.remove(listener);
+  }
+
+  void rebuild() {
+    for (var listener in _listeners) {
+      listener();
+    }
+  }
+
+  @override
+  Null get value => null;
+}