startCustomRecording method 
    
      
void
startCustomRecording(
{ - Duration interval = const Duration(seconds: 1), 
}) 
    
    
  Implementation
  void startCustomRecording({Duration interval = const Duration(seconds: 1)}) {
  _customTimer?.cancel(); // Cancel if any previous timer exists
  _customTimerSubject.add(0); // Reset timer to 0 seconds
  // Start custom timer
  _customTimer = Timer.periodic(const Duration(seconds: 1), (_) {
    final int currentSeconds = _customTimerSubject.value + 1;
    _customTimerSubject.add(currentSeconds); // Update elapsed time
  });
  // Start capturing frames at specified intervals
  Timer.periodic(interval, (_) async {
    await _captureCustomRecordingFrame();
  });
}