Test

add serializable protocol #6517

Job	Run time
py=3.13-upstream	28s
doctests	28s
py=3.11-min_deps	27s
os=ubuntu-latest, py=3.13, deps=minimal	17s
os=ubuntu-latest, py=3.12, deps=optional	27s
os=ubuntu-latest, py=3.11, deps=minimal	27s
os=macos-latest, py=3.13, deps=optional	16s
os=ubuntu-latest, py=3.12, deps=minimal	27s
os=macos-latest, py=3.11, deps=optional	57s
os=windows-latest, py=3.11, deps=optional	20s
os=windows-latest, py=3.13, deps=optional	20s
os=ubuntu-latest, py=3.13, deps=optional	27s
os=ubuntu-latest, py=3.11, deps=optional	14s
Test complete	3s
	5m 38s

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