feat(lib): missing Timer will warn or panic #2311

Job	Run time
Check Style	11s
Verify hyper.h is up to date	42s
Test with Miri	1m 33s
Test C API (FFI)	32s
features	26s
Check MSRV	1m 38s
Test stable on ubuntu-latest	2m 8s
udeps	22s
Test stable on windows-latest	4m 25s
Test stable on macOS-latest	2m 44s
Test beta on ubuntu-latest	2m 5s
Test beta on windows-latest	3m 10s
Test beta on macOS-latest	1m 52s
Test nightly on ubuntu-latest	1m 30s
Test nightly on windows-latest	4m 4s
Test nightly on macOS-latest	3m 53s
Build docs	34s
Check exposed types	33s
CI is green	0s
	32m 22s

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