public List<Integer> getUnreadFieldIndexes(List<String> readFields) {
    ArrayList<Integer> result = new ArrayList<>();
    for (PdxField ft : fields) {
      if (!ft.isDeleted() && !readFields.contains(ft.getFieldName())) {
        result.add(ft.getFieldIndex());
      }
    }
    return result;
  }
@param readFields the fields that have been read
@return a List of fields that have not been read (may be empty).
geode-core/src/main/java/org/apache/geode/pdx/internal/PdxType.java