Rust

Add option to specify persistence path #59

Job	Run time
Format + check + test	4m 55s
android	1m 13s
cargo-deny aarch64-apple-darwin	40s
Check wasm32 + wasm-bindgen	3m 55s
cargo-deny aarch64-linux-android	40s
Check Windows	5m 38s
cargo-deny i686-pc-windows-gnu	40s
cargo-deny i686-pc-windows-msvc	37s
cargo-deny i686-unknown-linux-gnu	38s
cargo-deny wasm32-unknown-unknown	39s
cargo-deny x86_64-apple-darwin	39s
cargo-deny x86_64-pc-windows-gnu	41s
cargo-deny x86_64-pc-windows-msvc	38s
cargo-deny x86_64-unknown-linux-gnu	38s
cargo-deny x86_64-unknown-linux-musl	39s
cargo-deny x86_64-unknown-redox	40s
	23m 30s

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