pub fn make_singleton_guard(
_module: &dyn CameraModule<CameraType = WrappedCamera, Guard = WebcamTerminateGuard>,
) -> Result<WebcamTerminateGuard>pub fn make_singleton_guard(
_module: &dyn CameraModule<CameraType = WrappedCamera, Guard = WebcamTerminateGuard>,
) -> Result<WebcamTerminateGuard>