code: public function getAllEventsAsJson()
      {
          $cache = $this->cache;
  
          if ($cache::has(self::ALL_EVENTS_TO_JSON_KEY)) {
              return $cache::get(self::ALL_EVENTS_TO_JSON_KEY);
          }
  
          $allEvents = $this->calendarEventsEngine
              ->formatEventsToJson($this->getAllEvents());
          $allEventsToJson = json_encode($allEvents);
          $cache::put(self::ALL_EVENTS_TO_JSON_KEY, $allEventsToJson, $this->cacheTimeToLive);
  
          return $allEventsToJson;
  
      }
docs: Get all events JSON
  
  @return string