Test IO file sizes in Rust and array sizes in Python doctests

[robert3005]

Python io doc tests check compressed size in bytes since that's what they're talking about. Keep the file size test as a rust test

[codspeed-hq]

Merging this PR will improve performance by 25.6%

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 3 improved benchmarks
✅ 2194 untouched benchmarks
⏩ 218 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	WallTime	arrow_checked_add_u32_neon[16384]	20.4 µs	13.3 µs	+53.75%
⚡	WallTime	words_gather_scalar_avx2[65536]	9.4 µs	8.2 µs	+13.59%
⚡	Simulation	allocate_drop_arrow[0]	456.9 ns	402.7 ns	+13.45%

Tip

Curious why performance improved? Comment @codspeedbot explain why performance improved on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing rk/python-io-doctest-size (c0aae71) with develop (ad925fd)}

Footnotes

1. 218 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[joseph-isaacs]

Can we move this into a rust test on the written file size. It really useful to know when we change file size

[robert3005]

Here you go, there's a rust test now, I kept the python change since this is useful for docs