the borg files cache can be rather large, because it keeps some information about all files that have been processed recently.

lz4 is a very fast compression / decompression algorithm, so we could try to use it to lower the in-memory footprint of the files cache entries.

before implementing this, we should check how big the savings typically are - to determine whether it is worthwhile doing

Lots of error cases are untested, which is worth improving but not urgently so.
Here are some chunks of code that should better be tested (line numbers as found in rev 0448bfbb9a1845a3cca5d07a32fdd4590f538713, [HTML coverage report](https://github.com/cython/cython/suites/2745137547/artifa

A program can tell that it's running on PyBoy because the buttons always change right at vblank.

To reproduce:

1. Install PyBoy
2. Start the test ROM "Telling LYs?" (which I have precompiled for your convenience here)
3. Press all 8 buttons in any order
4. Watch the arrow sprite at the right side

Expect: Arrow moves after each press, followed

rasterio.warp.reproject takes a kwargs parameter, which is passed to the "transformation function". It is not by any means clear what this means. What transformation function? What are the allowed values for kwargs? Can this please be expanded on? Thanks.

An option like $ fio cat --bounds w s e n --bounds-crs <crs> --dst-crs <crs> would allow for filtering prior to reprojection, like $ ogr2ogr -spat w s e n -spat_srs <crs>.

See Toblerity/Fiona#210 for a discussion about standardizing bounding boxes as --bounds w s e n rather than --bbox w,s,e,n.

This could be done adding a new line in scikit-ci-yml.

The line could be

- twine check dist/*

See https://github.com/scikit-build/scikit-build/blob/5f558d3cc063f41b04cb21bd229b0b3faae0f4cb/scikit-ci.yml#L57-L58