code: public <T extends IEntity> void downloadPDFAsync(T entity, CallbackHandler callbackHandler) throws FMSException {
          if(!isAvailableAsPDF(entity)) {
              throw new FMSException("Following entity: " + entity.getClass().getSimpleName() + " cannot be exported as PDF (Async) " );
          }
          IntuitMessage intuitMessage = prepareDownloadPDF(entity);
  
          //set callback handler
          intuitMessage.getRequestElements().setCallbackHandler(callbackHandler);
  
          //execute async interceptors
          executeAsyncInterceptors(intuitMessage);
      }
docs: Method to download the file for the given entity id in asynchronous fashion
  
  @param entity
  the entity
  @param callbackHandler
  the callback handler
  @throws FMSException
  throws FMSException