How best to listen for a Spark event "Subscribed/UserSubscribed"

I am trying to decide the best way to listen for a Spark "Subscription\UserSubscribed" event. I tried creating a listener, but I can not seem to capture the event which is broadcast when a user subscribes to a plan. The event broadcaster is Laravel\Spark\Events\Subscription\UserSubscribed. I tried this....

namespace App\Listeners;

use App\User;
use App\Notifications\UserDidRegister;
use Illuminate\Queue\InteractsWithQueue;
use Illuminate\Contracts\Queue\ShouldQueue;
use Laravel\Spark\Events\Subscription\UserSubscribed;

class CreatedNewUser
{
    public $user;

    /**
     * Create the event listener.
     *
     * @return void
     */
    public function __construct(User $user)
    {
        $this->user = $user;
    }

    /**
     * Handle the event.
     *
     * @param  UserSubscribed  $event
     * @return void
     */
    public function handle(UserSubscribed $event)
    {
//        $user = $event->user;
//        $event->fromRegistration->notify(new UserDidRegister($user));
    }
}

local.DEBUG: The UserSubscribed event has been captured! 

I would like to send a notification email after capturing this event. Any help is appreciated.