correct the chunk size by adding header size (#395) #1415

Job	Run time
check-docs / make-docs (html)	2m 5s
check-package / init-store	7s
check-docs / make-docs (doctest)	1m 58s
check-docs / make-docs (linkcheck)	2m 2s
check-schema / schema	12s
check-typing / mypy	2m 3s
check-package / pkg-build (ubuntu-latest)	21s
check-package / pkg-check (ubuntu-latest, 3.8)	2m 55s
check-package / pkg-check (ubuntu-latest, 3.10)	2m 56s
check-package / pkg-check (macos-13, 3.8)	1m 49s
check-package / pkg-check (macos-13, 3.10)	1m 49s
check-package / pkg-check (windows-latest, 3.8)	3m 54s
check-package / pkg-check (windows-latest, 3.10)	2m 54s
check-package / pkg-guardian	1s
	25m 6s

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