docs(source): add down sampling doc #8282

Job	Run time
prepare	1s
build-docker-images (1.22.1)	1m 21s
build-for-android	2m 20s
build-docker-images (-alpine, 1.22.1)	1m 37s
build-kubernetes-tool	5m 30s
build-on-mac	1m 20s
build-docker-images (-dev, 1.22.1)	2m 49s
build-docker-images (-slim, 1.22.1)	1m 48s
build-docker-images (-slim-python, 1.22.1)	33s
build-docker-images (-full, 1.22.1)	2m 19s
build (1.22.1, linux/amd64, debian)	3m 38s
release	12s
	23m 28s

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