title: Prevent a Laravel notification to be sent
body: <p>I'm working on a feature to send a "cascade" or a chain of <a href="https://laravel.com/docs/5.8/notifications" rel="nofollow noreferrer">notifications</a> with a delay between them with different channel. For example:</p>
  
  <p>Email -> (30 minutes later) -> Push -> (30 minutes later) -> SMS</p>
  
  <p>That flow is working good, now is the user completes something or does an action I want the chain to stop. So I stop or prevent the notification to be sent. This is what I've tried, but nothing seems to <a href="https://media.giphy.com/media/xT0BKCQJDzoTaeQyA0/giphy.gif" rel="nofollow noreferrer">stop them</a>.</p>
  
  <p>I've tried:</p>
  
  <pre><code>public function via($notifiable)
  {
      if (whatever condition to stop) {
          return null; // also tried with return []
      }
  
      return ['mail'];
  }
  </code></pre>
  
  <p>Also </p>
  
  <pre><code>public function __construct(array $data = [])
  {
      if (whatever condition to stop) {
          exit; // are you desperate, bruh?
      }
  }
  </code></pre>
  
  <p>Is there something super obvious I'm not seeing? Might be related to our custom scheduler, tho.
  Do you have an idea where can I break the app to prevent the notification to be sent?</p>