code: @SuppressWarnings("SynchronizationOnLocalVariableOrMethodParameter")
  	private List<Long> getOrCreateBucketsValues(final Stopwatch stopwatch) {
  		synchronized (stopwatch) {
  			List<Long> values = getBucketsValues(stopwatch);
  			if (values == null) {
  				values = new ArrayList<>((int) warmupCounter);
  				stopwatch.setAttribute(ATTR_NAME_BUCKETS_VALUES, values);
  			}
  			return values;
  		}
  	}
docs: Get the bucket values attribute or create it if it does not exist.