uffer format supports the idea of extending the format over time in such a way that the code can still read data encoded with the old format.</p>
<h2><a href="#defining-your-protocol-format" name="defining-your-protocol-format"></a>Defining Your Protocol Format</h2>
<p>To create your address book application, you’ll need to start with a <code>.proto</code> file. The definitions in a <code>.proto</code> file are simple: you add a message for each data structure you want to serialize, then specify a name an