Never did it before, but just tried this:
- Arrange two clips to overlap to create a transition.
- With the transition selected:
- Add a blur effect, make the width wider.
- Add a ‘size and position’ effect. I selected ‘Slow Move Left’.
- Then increase the first ‘position’ number to make the ‘swish’ faster.
Maybe other keyframes could be added for easing and whatever.
My solution may not be great, but as I’ve never done it before, it gives you something.