clrghouz/app/Providers/AppServiceProvider.php

<?php

namespace App\Providers;

use Illuminate\Notifications\ChannelManager;
use Illuminate\Support\Facades\Notification;
use Illuminate\Support\ServiceProvider;

use App\Notifications\Channels\NetmailChannel;
use App\Models\Netmail;
use App\Traits\SingleOrFail;

class AppServiceProvider extends ServiceProvider
{
	use SingleOrFail;

	/**
	 * Register any application services.
	 *
	 * @return void
	 */
	public function register()
	{
		Notification::resolved(function (ChannelManager $service) {
			$service->extend('netmail', function ($app) {
				return new NetmailChannel($app->make(Netmail::class));
			});
		});
	}

	/**
	 * Bootstrap any application services.
	 *
	 * @return void
	 */
	public function boot()
	{
		static::bootSingleOrFail();
	}
}