toggleFlash method

Implementation

Future<void> toggleFlash() async {
  final availableFlashModes = [
    FlashMode.off,
    FlashMode.auto,
    FlashMode.always
  ];

  int currentIndex = availableFlashModes.indexOf(_flashMode);
  int nextIndex = (currentIndex + 1) % availableFlashModes.length;
  await setFlashMode(availableFlashModes[nextIndex]);
}