feat(lib): missing Timer will warn or panic #2312

Job	Run time
Check Style	4s
Verify hyper.h is up to date	33s
Test with Miri	1m 9s
features	17s
Test C API (FFI)	56s
Check MSRV	1m 31s
Test stable on ubuntu-latest	1m 11s
udeps	28s
Test stable on windows-latest	2m 6s
Test stable on macOS-latest	1m 48s
Test beta on ubuntu-latest	1m 7s
Test beta on windows-latest	2m 48s
Test beta on macOS-latest	1m 49s
Test nightly on ubuntu-latest	1m 16s
Test nightly on windows-latest	2m 37s
Test nightly on macOS-latest	2m 3s
Check exposed types	25s
Build docs	38s
CI is green	1s
	22m 47s

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