update mux #224

Job	Run time
Intra-doc links	3m 53s
Build target wasm32-unknown-unknown	4m 17s
Book tests	3m 51s
Build target wasm32-wasi	4m 2s
Bitrot check	1m 40s
Rustfmt	13s
Test on i686-unknown-linux-gnu	16m 13s
Test on ubuntu-latest	10m 14s
Test on i686-unknown-linux-gnu with beta features	15m 56s
Test on windows-latest	12m 45s
Test on i686-unknown-linux-gnu with nightly features	18m 18s
Test on macOS-latest	10m 56s
Test on ubuntu-latest with beta features	9m 51s
Test on windows-latest with beta features	12m 35s
Test on macOS-latest with beta features	11m 46s
Test on ubuntu-latest with nightly features	10m 42s
Test on windows-latest with nightly features	13m 49s
Test on macOS-latest with nightly features	11m 34s
	2h 52m 35s

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