如何在Laravel 5.5中实现事件

Question

The Laravel Eloquent Event docs give this example:

namespace App;

use App\Events\UserSaved;
use App\Events\UserDeleted;
use Illuminate\Notifications\Notifiable;
use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Authenticatable
{
    use Notifiable;

    /**
     * The event map for the model.
     *
     * @var array
     */
    protected $dispatchesEvents = [
        'saved' => UserSaved::class,
        'deleted' => UserDeleted::class,
    ];
}

I simply want to know what would go in a UserSaved::class to, let's say, add a hash id on the initial save. The docs are frustratingly opaque at this point!