protected void replyWithException(ClusterDistributionManager dm, ReplyException rex) {
      StreamingReplyMessage.send(getSender(), processorId, rex, dm, null, 0, 0, true);
    }
override in subclass to provide reply data. terminate by returning Token.END_OF_STREAM
geode-core/src/main/java/org/apache/geode/distributed/internal/streaming/StreamingOperation.java