refactor(lib): resolve unused warning #2190

Job	Run time
Verify hyper.h is up to date	42s
Check Style	18s
Check MSRV	4m 9s
Test with Miri	1m 20s
Test C API (FFI)	1m 13s
features	31s
Test stable on ubuntu-latest	2m 14s
udeps	37s
Test stable on windows-latest	2m 32s
Test stable on macOS-latest	2m 15s
Test beta on ubuntu-latest	2m 25s
Test beta on windows-latest	3m 2s
Test beta on macOS-latest	2m 43s
Test nightly on ubuntu-latest	2m 8s
Test nightly on windows-latest	2m 58s
Test nightly on macOS-latest	2m 41s
Build docs	0s
Check exposed types	0s
CI is green	0s
	31m 48s

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