docs: public ScheduledEntry<K, V> getByCompositeKey(K key) {
          Set<CompositeKey> candidateKeys = getCompositeKeys(key);
          ScheduledEntry<K, V> result = null;
          for (CompositeKey compositeKey : candidateKeys) {
              Integer second = secondsOfKeys.get(compositeKey);
              if (second != null) {
                  Map<Object, ScheduledEntry<K, V>> entries = scheduledEntries.get(second);
                  if (entries != null) {
                      result = entries.get(compositeKey);
                  }
              }
          }
          return result;
      }