@Override
  public void toData(DataOutput out,
      SerializationContext context) throws IOException {
    super.toData(out, context);
    DataSerializer.writeObject(this.context, out);
  }
It sends message one by one until it gets lastMessage. Have to handle scenario when message is
large, in that case message will be broken into chunks and then sent across.
geode-core/src/main/java/org/apache/geode/internal/cache/partitioned/PartitionedRegionFunctionStreamingMessage.java