You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/phaser/phaser/vendor/aho-corasick/src/packed
    
    the code of the file until where you have to start completion: /*!
A lower level API for packed multiple substring search, principally for a small
number of patterns.

    
# fn example() -> Option<()> {
let searcher = Config::new()
    .match_kind(MatchKind::LeftmostLongest)
    .builder()
    .add("foo")
    .add("foobar")
    .build()?;
let matches: Vec<usize> = searcher
    .find_iter("foobar")
    .map(|mat| mat.pattern())
    .collect();
assert_eq!(vec![1], matches);
# Some(()) }