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: e017.rs
    path of file: ./repos/newrustacean.com/src
    
    the code of the file until where you have to start completion: //! Point me where I need to go
//!
//!   - **Date:** August 5, 2016
//!   - **Subject:** A deep dive on references and pointers in Rust.
//!   - [**Audio**][mp3]
//!
//! [mp3]: https://www.podtrac.com/pts/redirect.mp3/cdn.newrustacean.com/file/newrustacean/e017.mp3
//!
//! <audio style="width: 100%" title="e017: Point me where I need to go" controls preload=metadata><source src="https://www.podtrac.com/pts/redirect.mp3/cdn.newrustace
    
pub fn demonstrate_match() {
    let four = 4;
    let ref_to_four = &four;

    // Here, if we try to reference the contents of `store` directly, we'll find
    // that it doesn't work: we get a type error.
    let store = DataStore::new(ref_to_four); // type: DataStore
    let optional_store = Some(store); // type: Option<DataStore>
    let contents = match optional_store {
        Some(store) => *store.contents,
        None => 0,
    };

    println!("{:?}", contents);
}