code: public function trigger($event, $target = null)
      {
          if (empty($this->_template) || !is_string($this->_template)) {
              throw new \InvalidArgumentException('ContentCollector must have a template-name');
          }
            
          $responseCollection = $this->getController()->getEventManager()->trigger($event, $target);
          $viewModel = new ViewModel();
          $viewModel->setTemplate($this->_template);
          foreach ($responseCollection as $i => $response) {
              if (is_string($response)) {
                  $template = $response;
                  $response = new ViewModel(array('target' => $target));
                  $response->setTemplate($template);
              }
              $viewModel->addChild($response, $this->_captureTo . $i);
          }
                  
          return $viewModel;
      }
docs: Trigger capture event
  
  @param   EventInterface $event
  @param   mixed|null  $target
  
  @return  ViewModel