@Override
  public byte[] readByteArray(PdxField f) {
    readFields.add(f.getFieldName());
    return pdxReader.readByteArray(f);
  }
Returns the indexes of the fields not read during deserialization.

@return the indexes of the unread fields
geode-core/src/main/java/org/apache/geode/pdx/internal/TrackingPdxReaderImpl.java