code: protected function renderV2()
      {
          $out = [];
  
          $messages = [];
  
          foreach ($this->messages as $message) {
              if ($message instanceof Payload) {
                  $out['payload'] = $message->render();
              } else {
                  $messages[] = $message->render();
              }
          }
  
          if (count($messages)) {
              $out['fulfillmentMessages'] = $messages;
          }
  
          if ($this->text) {
              $out['fulfillmentText'] = $this->text;
          }
  
          $outgoingContexts = [];
          foreach ($this->outgoingContexts as $outgoingContext) {
              $outContexts = [
                  'name' => $this->session.'/contexts/'.$outgoingContext->getName(),
              ];
  
              if ($outgoingContext->getLifespan()) {
                  $outContexts['lifespanCount'] = $outgoingContext->getLifespan();
              }
  
              if ($outgoingContext->getParameters()) {
                  $outContexts['parameters'] = $outgoingContext->getParameters();
              }
  
              $outgoingContexts[] = $outContexts;
          }
          $out['outputContexts'] = $outgoingContexts;
  
          return $out;
      }
docs: Render response as array for API V2.
  
  @param string $session session
  
  @return array