Different approach: add a PacketNumberSpace #210

Job	Run time
msrv	1m 23s
audit	25s
test (ubuntu-latest, stable)	43s
lint	35s
test (ubuntu-latest, beta)	47s
test (macos-latest, stable)	1m 1s
test-android (x86_64-linux-android, x86_64, 26)	1m 50s
test-aws-lc-rs	48s
test (windows-latest, stable)	3m 3s
test-android (x86_64-linux-android, x86_64, 25)	1m 43s
test on freebsd	3m 20s
test on illumos	4m 25s
test on netbsd	2m 59s
test-android (i686-linux-android, x86, 26)	1m 40s
test-android (i686-linux-android, x86, 25)	1m 41s
test on solaris	4m 27s
test wasm32-unknown-unknown	40s
	31m 30s

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