// TODO(b/160980469): remove support for the old serialization format after some time
    private static final boolean USE_LEGACY_SERIALIZATION = true;

    private final Object keys;
    private final Object values;

    SerializedForm(ImmutableMap<K, V> map) {
      if (USE_LEGACY_SERIALIZATION) {
        Object[] keys = new Object[map.size()];
        Object[] values = new Object[map.size()];