Fedeisas\LaravelMailCssInliner\LaravelMailCssInlinerServiceProvider::register PHP Method

    public function register()
    {
        $this->mergeConfigFrom(__DIR__ . '/../config/css-inliner.php', 'css-inliner');
        $this->app->singleton('Fedeisas\\LaravelMailCssInliner\\CssInlinerPlugin', function ($app) {
            return new CssInlinerPlugin($app['config']->get('css-inliner'));
        });
        $this->app->extend('swift.mailer', function (Swift_Mailer $swiftMailer, $app) {
            $inlinerPlugin = $app->make('Fedeisas\\LaravelMailCssInliner\\CssInlinerPlugin');
            $swiftMailer->registerPlugin($inlinerPlugin);
            return $swiftMailer;
        });
    }