I need my existing Flutter-based iPhone app to emit a simple vibration-style haptic feedback while it runs in the background. The trigger is purely time-based: the phone should buzz at regular intervals—ideally every few seconds, not a fixed schedule such as 30 or 60 seconds—until the user stops the feature from inside the app. The Flutter side is already complete; what’s missing is the iOS implementation. I’m happy for you to write the native portion in Swift and expose it to Dart through a MethodChannel (or, if you prefer, a custom Flutter plugin). All code must compile against the current stable Flutter SDK and the latest Xcode toolchain. Key points • Type of feedback: vibration • Trigger: automatic, at regular intervals • Interval: adjustable in code, defaulting to “every few seconds” Deliverables 1. Swift code (or plugin) that starts and stops the background haptic loop. 2. Dart wrapper with a simple API: start(intervalInMs), stop(). 3. Integration into my existing project plus a short README explaining any new entitlements or background modes I must enable. 4. Test build demonstrating that the haptics continue even when the app is in the background or the screen is locked. The work will be considered complete once the buzz fires reliably under those conditions on an actual device (iOS 16+), with no crashes or excessive battery drain.