@Override
  public Object[] readObjectArray(PdxField ft) {
    if (ft instanceof DefaultPdxField) {
      return null; // default array value
    }
    return dis.readObjectArray(getPositionForField(ft));
  }
@return size of each variable length field offset
geode-core/src/main/java/org/apache/geode/pdx/internal/PdxReaderImpl.java