Flutter Dio Token Refresh: Fixing the Race Condition Most Tutorials Miss

Quick experiment you can run in five minutes. Open your Flutter app. Find a screen that fires multiple API calls on load — dashboard, profile, anything that does this: @override void initState () { super . initState (); _loadProfile (); _loadNotifications (); _loadRecentActivity (); _loadUnreadMessages (); } Four API calls. Normal stuff. Now expire your access token (manually, or wait it out) and reload. Open your network inspector and count how many times /auth/refresh gets called. If you see 4