add client data cache for ip and username

src/client/app.rs

@@ -58,6 +58,11 @@ impl ApplicationHandler<ClientEvent> for App {
         let client = self.client.as_mut().unwrap();
         client.event(event, event_loop);
     }
+
+    fn exiting(&mut self, _: &ActiveEventLoop) {
+        let client = self.client.as_mut().unwrap();
+        client.exit();
+    }
 }
 
 impl AppHandle {