### Description It uses a lot of `std::string` in the jieba_ftparser and can be replaced by `string_view`. `string_view` doesn't allocate memory, so it's better than `std::string`.
Description
It uses a lot of
std::stringin the jieba_ftparser and can be replaced bystring_view.string_viewdoesn't allocate memory, so it's better thanstd::string.