code: private void cleanUpScheduledFuturesIfEmpty(Integer second, Map<Object, ScheduledEntry<K, V>> entries) {
          if (entries.isEmpty()) {
              scheduledEntries.remove(second);
  
              ScheduledFuture removedFeature = scheduledTaskMap.remove(second);
              if (removedFeature != null) {
                  removedFeature.cancel(false);
              }
          }
      }
docs: Cancels the scheduled future and removes the entries map for the given second If no entries are left
  <p/>
  Cleans up parent container (second -> entries map) if it doesn't hold anymore items this second.
  <p/>
  Cancels associated scheduler (second -> scheduler map ) if there are no more items to remove for this second.
  
  @param second  second at which this entry was scheduled to be evicted
  @param entries entries which were already scheduled to be evicted for this second