anonaddy/app/Notifications/UsernameReminder.php

<?php

namespace App\Notifications;

use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldBeEncrypted;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Notifications\Messages\MailMessage;
use Illuminate\Notifications\Notification;

class UsernameReminder extends Notification implements ShouldQueue, ShouldBeEncrypted
{
    use Queueable;

    /**
     * Get the notification's delivery channels.
     *
     * @param  mixed  $notifiable
     * @return array
     */
    public function via($notifiable)
    {
        return ['mail'];
    }

    /**
     * Get the mail representation of the notification.
     *
     * @param  mixed  $notifiable
     * @return \Illuminate\Notifications\Messages\MailMessage
     */
    public function toMail($notifiable)
    {
        return (new MailMessage)
            ->subject("AnonAddy Username Reminder")
            ->markdown('mail.username_reminder', [
                'username' => $notifiable->user->username
            ])
            ->withSwiftMessage(function ($message) {
                $message->getHeaders()
                        ->addTextHeader('Feedback-ID', 'UR:anonaddy');
            });
    }

    /**
     * Get the array representation of the notification.
     *
     * @param  mixed  $notifiable
     * @return array
     */
    public function toArray($notifiable)
    {
        return [
            //
        ];
    }
}