Here is a summary of the text in 1 paragraph: Symfony Events are an excellent way to build richer, more flexible, and maintainable applications. In this tutorial, you'll learn how to use Symfony's EventDispatcher Component to respond to events by sending SMS messages powered by Twilio's SMS API. You'll need prior experience with PHP and Symfony, as well as a Twilio account and mobile phone number. The application will dispatch a "usage.records.retrieved" event when the sole application route is requested, which subscribers can then respond to autonomously of any other process. The subscriber class uses Twilio's SMS API to send an SMS with the total cost of sending the messages. The tutorial guides you through creating the Event and Subscriber classes, configuring the application, and testing that it works.