feat(client): implement Clone for Tunnel #668

Job	Run time
Check Style	6s
semver	18s
Test with Miri	50s
Check MSRV (1.63)	3m 54s
features	40s
Test stable on windows-latest	1m 29s
Test stable on ubuntu-latest	32s
Test beta on windows-latest	1m 17s
Test stable on macos-latest	30s
Test beta on macos-latest	49s
Test nightly on ubuntu-latest	35s
Test beta on ubuntu-latest	1m 7s
Test nightly on windows-latest	1m 16s
Test nightly on macos-latest	49s
Build docs	13s
CI is green	2s
	14m 27s

Provide feedback