code: public final <S extends T> Wrapper<S> wrap(@Nullable S reference) {
      return new Wrapper<S>(this, reference);
    }
docs: Returns a wrapper of {@code reference} that implements {@link Wrapper#equals(Object)
  Object.equals()} such that {@code wrap(a).equals(wrap(b))} if and only if {@code equivalent(a,
  b)}.
  
  @since 10.0