code: @Override
    public <U> Page<U> map(final Function<? super T, ? extends U> converter) {
      return new PageImpl<>(this.getConvertedContent(converter), getPageable(), this.total);
    }
docs: /*
  (non-Javadoc)
  
  @see
  org.springframework.data.domain.Slice#transform(org.springframework.core.convert.converter.
  Converter)