Rust

Update Rust crate log to 0.4.21 #537

Job	Run time
build-docker (1.63, x86_64-unknown-freebsd)	1m 37s
build-unix (1.63, ubuntu)	3m 26s
build-docker (stable, x86_64-unknown-freebsd)	1m 35s
build-windows (i686, msvc, 1.63)	4m 15s
build-unix (1.63, macos)	4m 59s
build-docker (nightly, x86_64-unknown-freebsd)	1m 46s
build-windows (i686, msvc, stable)	1m 52s
build-unix (stable, ubuntu)	40s
build-windows (i686, msvc, nightly)	1m 4s
build-unix (stable, macos)	40s
build-windows (x86_64, msvc, 1.63)	7m 11s
build-unix (nightly, ubuntu)	33s
build-windows (x86_64, msvc, stable)	1m 11s
build-unix (nightly, macos)	48s
build-windows (x86_64, msvc, nightly)	53s
build-windows (aarch64, msvc, 1.63)	7m 59s
build-windows (aarch64, msvc, stable)	1m 11s
build-windows (aarch64, msvc, nightly)	51s
	42m 31s

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