@Override
  public int getLocalSize() {
    if (cache.isClosed()) {
      return 0;
    }
    return getIdToType().size();
  }
adds a PdxType for a field to a {@code className => Set<PdxType>} map
geode-core/src/main/java/org/apache/geode/pdx/internal/PeerTypeRegistration.java