@Override
    public void toData(DataOutput out,
        SerializationContext context) throws IOException {
      int startIndex = index;
      index += chunkSize;
      list.toData(out, context, startIndex, chunkSize, sendKeys, sendObjects);
    }
Chunker is used to send a VersionedObjectList to a client in pieces. It works by pretending to
be a VersionedObjectList during serialization and writing only a portion of the list in each
invocation of toData().
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/VersionedObjectList.java