Guard `Packer` buffer protocol hooks with Cython critical sections (#… #450

Job	Run time
Run test with Python 3.14t on ubuntu-latest	1m 13s
Run test with Python 3.14 on ubuntu-latest	37s
Run test with Python 3.12 on ubuntu-latest	27s
Run test with Python 3.10 on windows-latest	1m 15s
Run test with Python 3.15t on windows-11-arm	3m 3s
Run test with Python 3.11 on ubuntu-latest	26s
Run test with Python 3.15 on windows-11-arm	3m 25s
Run test with Python 3.12 on windows-latest	58s
Run test with Python 3.15t on ubuntu-latest	1m 20s
Run test with Python 3.14 on windows-latest	1m 2s
Run test with Python 3.13 on windows-latest	57s
Run test with Python 3.11 on windows-latest	1m 5s
Run test with Python 3.15 on ubuntu-latest	37s
Run test with Python 3.14 on macos-latest	33s
Run test with Python 3.13 on ubuntu-latest	33s
Run test with Python 3.14 on windows-11-arm	1m 2s
Run test with Python 3.13 on macos-latest	25s
Run test with Python 3.15t on windows-latest	2m 37s
Run test with Python 3.14t on windows-latest	2m 41s
Run test with Python 3.11 on macos-latest	26s
Run test with Python 3.12 on windows-11-arm	1m 35s
Run test with Python 3.15t on macos-latest	1m 21s
Run test with Python 3.14t on macos-latest	2m 18s
Run test with Python 3.10 on ubuntu-latest	33s
Run test with Python 3.11 on windows-11-arm	2m 30s
Run test with Python 3.15 on macos-latest	51s
Run test with Python 3.10 on macos-latest	41s
Run test with Python 3.15 on windows-latest	1m 44s
Run test with Python 3.12 on macos-latest	23s
Run test with Python 3.14t on windows-11-arm	3m 20s
Run test with Python 3.13 on windows-11-arm	1m 8s
	41m 6s

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