code: public function initializeContainer(Application $application, array $extensions = array(), array $compilerPasses = array())
      {
          $class = $this->getContainerClass($application);
          $cache = new ConfigCache($this->cacheDir.'/'.$class.'.php', $application->isDebug());
          if (!$cache->isFresh()) {
              $container = $this->wrappedInitializer->initializeContainer($application, $extensions, $compilerPasses);
  
              $this->dumpContainer($cache, $container, $class, 'Container');
          }
  
          require_once $cache;
  
          return new $class();
      }
docs: Returns a fully built, ready to use Container
  
  @param Application                   $application
  @param array|ExtensionInterface[]    $extensions
  @param array|CompilerPassInterface[] $compilerPasses
  
  @return ContainerInterface