@Override
    public String toString() {
      return "TXLockUpdateParticipantsReplyMessage processorId=" + super.processorId + "; sender="
          + getSender();
    }
The simple reply message that the sender waits for
geode-core/src/main/java/org/apache/geode/internal/cache/locks/TXLockUpdateParticipantsMessage.java