When dumping geometry to GeoJSON, Features are made in an iterator and dumped as they are generated. This saves time and memory compared to precomputing all Features, then dumping the whole list of them.
Triangulating datasets is slightly more efficient. Some Polygons were formed and then immediately thrown after fetching their coordinates. The coordinates are passed around directly instead.
The time taken to generate polygons when exporting geometry is logged, for the sake of benchmarking.