Fix some issues pointed out by Clippy in examples and tests #67

Job	Run time
cargo-deny (advisories)	18s
lint	38s
cargo-deny (bans licenses sources)	18s
aarch64-apple-darwin / build	1m 42s
aarch64-apple-ios / build	1m 45s
aarch64-unknown-linux-gnu / build	45s
aarch64-unknown-linux-musl / build	1m 16s
arm-linux-androideabi / build	41s
armv7-linux-androideabi / build	45s
i686-pc-windows-gnu / build	3m 58s
i686-pc-windows-msvc / build	2m 19s
i686-unknown-linux-gnu / build	44s
i686-unknown-linux-musl / build	1m 19s
msrv-aarch64-apple-darwin / build	1m 29s
msrv-x86_64-pc-windows-msvc / build	2m 17s
msrv-arm-linux-androideabi / build	1m 34s
msrv-x86_64-unknown-freebsd / build	1m 32s
msrv-x86_64-unknown-linux-gnu / build	1m 30s
msrv-x86_64-unknown-linux-musl / build	1m 35s
msrv-x86_64-unknown-netbsd / build	3m 2s
x86_64-apple-darwin / build	2m 33s
x86_64-pc-windows-gnu / build	2m 33s
x86_64-unknown-freebsd / build	2m 17s
x86_64-pc-windows-msvc / build	3m 38s
x86_64-unknown-linux-gnu / build	55s
x86_64-unknown-linux-musl / build	54s
x86_64-unknown-netbsd / build	39s
	42m 56s

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