namespace std {
template <class charT, class traits = char_traits<charT>>
class istreambuf_iterator<charT, traits>::proxy { // exposition only
charT keep_;
basic_streambuf<charT,traits>* sbuf_;
proxy(charT c, basic_streambuf<charT,traits>* sbuf)
: keep_(c), sbuf_(sbuf) { }
public:
charT operator*() { return keep_; }
};
}