Pick up protocol 21 #3922

Job	Run time
check-git-rev-deps	16s
build-fuzz	48s
build-and-test (msrv, ubuntu-latest, x86_64-unknown-linux-gnu)	4m 28s
cargo-deny (advisories)	44s
build-and-test (msrv, ubuntu-latest, aarch64-unknown-linux-gnu, true)	2m 32s
cargo-deny (bans licenses sources)	43s
docs	2m 9s
build-and-test (msrv, macos-latest, x86_64-apple-darwin)	25m 57s
build-and-test (msrv, macos-latest, aarch64-apple-darwin)	16m 23s
fmt	12s
build-and-test (msrv, windows-latest, x86_64-pc-windows-msvc)	13m 54s
publish-dry-run	0s
readme	32s
build-and-test (latest, ubuntu-latest, x86_64-unknown-linux-gnu)	5m 3s
build-and-test (latest, ubuntu-latest, aarch64-unknown-linux-gnu, true)	2m 41s
rust-analyzer-compat	2m 34s
semver-checks	3m 57s
build-and-test (latest, macos-latest, x86_64-apple-darwin)	14m 4s
build-and-test (latest, macos-latest, aarch64-apple-darwin)	16m 31s
build-and-test (latest, windows-latest, x86_64-pc-windows-msvc)	13m 11s
complete	1s
	2h 6m 40s

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