refactor: avoid temporary allocation in `Resource::get_best_key` #10359

Job	Run time
markdown_lint	3s
Typos Check	4s
Unit tests on ubuntu-latest	23m 49s
Lints and doc tests on ubuntu-latest	11m 58s
Unit tests on windows-latest	38m 16s
Lints and doc tests on windows-latest	18m 6s
Unit tests on macos-13	13m 1s
Lints and doc tests on macos-13	18m 57s
Unit tests on macos-14	12m 43s
Lints and doc tests on macos-14	7m 31s
Memory leak checks	2m 21s
CI status checks	1s
	2h 26m 50s

Provide feedback