Expose `openHandles` #313

Job	Run time
stylish-haskell (9.6.6, 3.12.1.0, ubuntu-latest)	12m 15s
cabal-fmt (9.6.6, 3.12.1.0, ubuntu-latest)	2m 58s
cabal-check (9.6.6, 3.10.3.0, ubuntu-latest)	2m 16s
build (8.10.7, 3.12.1.0, ubuntu-latest)	6m 1s
build (8.10.7, 3.12.1.0, windows-latest)	7m 48s
build (8.10.7, 3.12.1.0, macOS-13)	15m 9s
build (9.2.8, 3.12.1.0, ubuntu-latest)	5m 18s
build (9.2.8, 3.12.1.0, windows-latest)	7m 55s
build (9.2.8, 3.12.1.0, macOS-13)	9m 41s
build (9.4.8, 3.12.1.0, ubuntu-latest)	5m 52s
build (9.4.8, 3.12.1.0, windows-latest)	7m 53s
build (9.4.8, 3.12.1.0, macOS-13)	9m 31s
build (9.6.6, 3.12.1.0, ubuntu-latest)	6m 1s
build (9.6.6, 3.12.1.0, windows-latest)	5m 51s
build (9.6.6, 3.12.1.0, macOS-13)	12m 16s
build (9.8.2, 3.12.1.0, ubuntu-latest)	4m 27s
build (9.8.2, 3.12.1.0, windows-latest)	10m 0s
build (9.8.2, 3.12.1.0, macOS-13)	11m 56s
build (9.10.1, 3.12.1.0, ubuntu-latest)	3m 56s
build (9.10.1, 3.12.1.0, windows-latest)	8m 20s
build (9.10.1, 3.12.1.0, macOS-13)	13m 16s
build (9.6.6, 3.12.1.0, ubuntu-latest, no-debug)	6m 1s
	2h 54m 41s

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