docs: @Override
      public Collection<IQueueMessage<ID, DATA>> getOrphanMessages(long thresholdTimestampMs) {
          if (isEphemeralDisabled()) {
              return null;
          }
          Collection<IQueueMessage<ID, DATA>> orphanMessages = new HashSet<>();
          long now = System.currentTimeMillis();
          ephemeralStorage.forEach((key, msg) -> {
              if (msg.getQueueTimestamp().getTime() + thresholdTimestampMs < now)
                  orphanMessages.add(msg);
          });
          return orphanMessages;
      }