chore: change std sleep to tokio sleep #468

Job	Run time
linters (ubuntu-latest)	2m 48s
unit-test (ubuntu-latest)	3m 50s
linters (macos-latest)	1m 53s
build-examples (ubuntu-latest)	2m 16s
unit-test (macos-latest)	2m 35s
security-audit	3m 50s
build-examples (macos-latest)	1m 46s
unit-test (windows-2019)	5m 57s
build-examples (windows-2019)	6m 6s
ci	1s
	31m 2s

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