How to determine when the tiles are all fetched?

[srfoster]

Thanks again for making this package!

I've been using it to generate picts of maps. It's already been enormously helpful!

There's just one thing. I'd like to detect when the tiles are finished downloading so that the pict can be safely generated without missing tiles.

I thought I could maybe do it by checking (get-download-backlog) -- but that doesn't seem to be working.

I've also used just a simple (sleep X) -- which works, but is gross.

Any advice? Here's my code if it helps:

https://github.com/thoughtstem/map-picts/blob/master/map-pict.rkt

[dancormier]

@dependabot rebase