proto: Connection side enum #5186

Job	Run time
test on netbsd	4m 56s
test on solaris	6h 0m 0s
audit	28s
lint	1m 22s
msrv	1m 12s
test-aws-lc-rs	3m 39s
test on freebsd	4m 25s
test on illumos	6m 57s
test wasm32-unknown-unknown	1m 22s
features (ubuntu-latest)	1h 21m 31s
test (ubuntu-latest, stable)	1m 30s
features (macos-latest)	27m 48s
test-android (x86_64-linux-android, x86_64, 26)	3m 40s
test (ubuntu-latest, beta)	1m 31s
features (windows-latest)	48m 59s
test-android (i686-linux-android, x86, 26)	3m 11s
test (macos-latest, stable)	1m 22s
test (windows-latest, stable)	3m 26s
	9h 17m 19s

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