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doc: specify thread safety for each data structure #274

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Job	Run time
build (ubuntu-22.04)	9m 34s
build (ubuntu-24.04)	9m 15s
build (macos-13)	18m 24s
build (macos-14)	8m 7s
build (windows-2022)	15m 46s
	1h 1m 6s