docs: public TransactionConfidence seen(Sha256Hash hash, PeerAddress byPeer) {
          TransactionConfidence confidence;
          boolean fresh = false;
          lock.lock();
          try {
              cleanTable();
              confidence = getOrCreate(hash);
              fresh = confidence.markBroadcastBy(byPeer);
          } finally {
              lock.unlock();
          }
          if (fresh)
              confidence.queueListeners(TransactionConfidence.Listener.ChangeReason.SEEN_PEERS);
          return confidence;
      }