Author here. This is a pretty simple script and I suspect there may be smarter ways to do this but it's been useful for me and others, so thought I'd share it.
thanks this looks really useful... what are your thoughts on continuations?
haha, you're the first person to ask! I once wrote a BPM / Workflow engine using serializable continuations and it worked quite well. I've since been surprised that they don't seemed to be taken off.