@Override
  protected synchronized PdxReaderImpl getUnmodifiableReader(String fieldName) {
    if (dirtyFields != null) {
      PdxField f = getPdxType().getPdxField(fieldName);
      if (f != null) {
        if (dirtyFields[f.getFieldIndex()] != null) {
          return getUnmodifiableReader();
        }
      }
    }
    return new PdxReaderImpl(this);
  }
Flush pending writes if the given field is dirty.
geode-core/src/main/java/org/apache/geode/pdx/internal/WritablePdxInstanceImpl.java