code: public function boot()
      {
          $this->app->when(SmsGatewayChannel::class)
              ->needs(SmsGatewayClient::class)
              ->give(function () {
                  $config = $this->app['config']['services.smsgateway'];
  
                  return new SmsGatewayClient(
                      new HttpClient,
                      $config['email'],
                      $config['password'],
                      $config['device']
                  );
              });
      }
docs: Boot the application services.
  
  @return void