std::basic_stringbuf

namespace std {
  template <class CharT, class Traits = char_traits<CharT>,
            class Allocator = allocator<CharT> >
  class basic_stringbuf : public basic_streambuf<CharT, Traits>;

  using stringbuf  = basic_stringbuf<char>;
  using wstringbuf = basic_stringbuf<wchar_t>;
}