Add missing close calls #552

Job	Run time
rust_ci (windows-latest, beta)	3m 7s
rust_ci (macos-latest, stable)	47s
rust_ci (ubuntu-latest, stable)	1m 5s
rust_ci (macos-latest, beta)	1m 41s
rust_ci (windows-latest, stable)	2m 35s
rust_ci (ubuntu-latest, nightly)	1m 48s
rust_ci (ubuntu-latest, beta)	1m 50s
rust_ci (windows-latest, nightly)	3m 12s
rust_ci (macos-latest, nightly)	1m 41s
	17m 46s

Provide feedback