Add stateless doc, prefer stateless mode and disable legacy SSE by default #2535

Job	Run time
build (windows-latest, Release)	11m 41s
build (macos-latest, Debug)	4m 39s
build (ubuntu-latest, Release)	13m 48s
build (ubuntu-latest, Debug)	12m 59s
build (windows-latest, Debug)	12m 25s
build (macos-latest, Release)	7m 25s
publish-coverage	0s
	1h 2m 57s

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