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: transactions.rs
    path of file: ./repos/phaser/phaser/vendor/winreg/examples
    
    the code of the file until where you have to start completion: // Copyright 2015, Igor Shaula
// Licensed under the MIT License <LICENSE or
// http://opensource.org/licenses/MI
    
fn main() -> io::Result<()> {
    let t = Transaction::new()?;
    let hkcu = RegKey::predef(HKEY_CURRENT_USER);
    let (key, _disp) = hkcu.create_subkey_transacted("Software\\RustTransaction", &t)?;
    key.set_value("TestQWORD", &1_234_567_891_011_121_314u64)?;
    key.set_value("TestDWORD", &1_234_567_890u32)?;

    println!("Commit transaction? [y/N]:");
    let mut input = String::new();
    io::stdin().read_line(&mut input)?;
    input = input.trim_end().to_owned();
    if input == "y" || input == "Y" {
        t.commit()?;
        println!("Transaction committed.");
    } else {
        // this is optional, if transaction wasn't committed,
        // it will be rolled back on disposal
        t.rollback()?;

        println!("Transaction wasn't committed, it will be rolled back.");
    }

    Ok(())
}