code: public synchronized void startAttributePolling(final AttributeImpl attr) throws DevFailed {
          addAttributePolling(attr);
          LOGGER.debug("starting attribute {} for polling on device {}", attr.getName(), deviceName);
          if (attr.getPollingPeriod() != 0) {
              attributeCacheMap.get(attr).startRefresh(POLLING_POOL);
          }
      }
docs: Start attribute polling
  
  @param attr
  The attribute to poll
  @throws DevFailed