Extending the module's API
There are many ways we can extend our module, for example, we could make it support more MP3 types, but this is merely leg work. It just takes finding out the different sync words and bitrates for different types of MP3, and then adding these to the relevant places.
For a more interesting venture, we could extend the API, creating more options for our module users.
Since we use a stream to read our MP3 file, we could allow the user to pass in either a filename or a stream of MP3 data, offering both ease (with a simple filename) and flexibility (with streams). This way we could start a download stream, STDIN stream, or in fact any stream of MP3 data.
We'll pick up our module from where we left it at the end ...