code: public CampaignTrackingService getCampaignTrackingService() {
          if (_campaignTrackingService == null) {
              synchronized (CCApi2.class) {
                  if (_campaignTrackingService == null) {
                      _campaignTrackingService = _retrofit.create(CampaignTrackingService.class);
                  }
              }
          }
  
          return _campaignTrackingService;
      }
docs: Gets the campaign tracking service.
  
  @return the campaign tracking service