Rust

Update Rust crate log to 0.4.21 #535

Job	Run time
build-unix (1.63, ubuntu)	3m 29s
build-docker (1.63, x86_64-unknown-freebsd)	1m 33s
build-unix (1.63, macos)	5m 59s
build-windows (i686, msvc, 1.63)	4m 11s
build-docker (stable, x86_64-unknown-freebsd)	1m 37s
build-unix (stable, ubuntu)	22s
build-windows (i686, msvc, stable)	2m 22s
build-docker (nightly, x86_64-unknown-freebsd)	1m 35s
build-windows (i686, msvc, nightly)	1m 11s
build-unix (stable, macos)	47s
build-windows (x86_64, msvc, 1.63)	4m 7s
build-unix (nightly, ubuntu)	32s
build-unix (nightly, macos)	1m 17s
build-windows (x86_64, msvc, stable)	1m 20s
build-windows (x86_64, msvc, nightly)	1m 32s
build-windows (aarch64, msvc, 1.63)	4m 16s
build-windows (aarch64, msvc, stable)	48s
build-windows (aarch64, msvc, nightly)	51s
	37m 49s

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