code: private boolean cancelAndCleanUpIfEmpty(Integer second, Map<Object, ScheduledEntry<K, V>> entries, Object key,
                                              ScheduledEntry<K, V> entryToRemove) {
          ScheduledEntry<K, V> entry = entries.get(key);
          if (entry == null || !entry.equals(entryToRemove)) {
              return false;
          }
          entries.remove(key);
          cleanUpScheduledFuturesIfEmpty(second, entries);
          return true;
      }
docs: Removes the entry if it exists from being scheduled to be evicted.
  <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.
  <p/>
  Returns associated scheduled entry.
  
  @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
  @param key           entry key
  @param entryToRemove entry value that is expected to exist in the map
  @return true if entryToRemove exists in the map and removed