csv文件中进行键值查询的引擎

示例

let opts = EngineOptions::default();
let mut engine: Engine<String, YourType> = Engine::from_file_with_opts("file.csv", YourType::make_key, opts).unwrap();
let value = engine.get_from_file("key");
println!("{:?}", value);

lib.rs:

从大文件中查询csv行