Add the parameters for the audio widget and code up the logic for the play interaction.
This is a companion discussion topic for the original entry at https://www.raywenderlich.com/20983402-creating-custom-reusable-widgets-in-flutter/lessons/5
This is a companion discussion topic for the original entry at https://www.raywenderlich.com/20983402-creating-custom-reusable-widgets-in-flutter/lessons/5