// This effectively discards the very large initial flate setup cost,
	// as well as the initialization of bigBuf.
	runOnce(&bytes.Buffer{})
	b.ResetTimer()

	b.RunParallel(func(pb *testing.PB) {
		var buf bytes.Buffer
		for pb.Next() {
			runOnce(&buf)
		}
	})
}

func writeTestsToFS(tests []WriteTest) fs.FS {
	fsys := fstest.MapFS{}
	for _, wt := range tests {