jQuery / Twitter Bootstrap data-loading-text button with delay

In the documentation page, there is a file being loaded called application.js. http://twitter.github.com/bootstrap/assets/js/application.js

// button state demo
$('#fat-btn')
    .click(function () {
        var btn = $(this)
        btn.button('loading')
        setTimeout(function () {
            btn.button('reset')
        }, 3000)
    });