code: protected function resolveKernel()
  	{
  		if ($this->kernel !== null) {
  			return $this->kernel;
  		}
  
  		$class = 'Symfony\Component\EventDispatcher\EventDispatcherInterface';
  		$eventDispatcher = $this->container->isBound($class) ?
  			$this->container->resolve($class) : null;
  
  		$kernel = new Kernel(
  			$this->getRouter(),
  			$this->requests,
  			$this->errorHandler,
  			$eventDispatcher
  		);
  
  		return $this->kernel = $this->resolveStack()
  			->resolve($kernel);
  	}
docs: Resolve the HTTP kernel.
  
  @return HttpKernelInterface