Ability to process features one by one

[mourner]

This may be a bit similar to #26 but has a different purpose: it would make it possible to make geojson-vt accept data in a stream, without allocating the whole input data in memory first. cc @kkaefer

[kkaefer]

Thanks for ticketing. Is there anything different implementation-wise to #26?

[mourner]

The only difference is that here we don't care about removal (which can be very tricky). And we would couple this with #29 to make a command that accepts a stream.

[aaronlidman]

This would be very helpful for larger datasets I'm working with right now and useful for compatibility with tools we've built to work with tippecanoe.

[dmfenton]

How would one go about this? I'm interested in giving it a go.

[METACEO]

I'd also be interested in giving this a go as I'm working with many gigabytes of data on the server side and the indexing is currently taking 6+ minutes and is blocking the rest of the event loop.

#92 is also interesting to me, too.

(Great project @mourner !)

[4xle]

@mourner I've taken a kick at getting tiles as a low-memory stream output on a constrained backend system here https://github.com/4xle/geojson-vt-stream.
I can't find any PR guidelines and am getting errors running your test suite normally (without my changes), but if I can get those sorted out and you send me any PR guidelines I'd happily turn what I've got into a PR.