QPDF_Stream::addTokenFilter(
    PointerHolder<QPDFObjectHandle::TokenFilter> token_filter)
{
    this->token_filters.push_back(token_filter);
}
QPDF_Stream::addTokenFilter(
    PointerHolder<QPDFObjectHandle::TokenFilter> token_filter)
{
    this->token_filters.push_back(token_filter);
}