Function TBasicString operator+

util/generic/string.h:934–937

     */

    friend TBasicString operator+(TBasicString&& s1, const TBasicString& s2) Y_WARN_UNUSED_RESULT {
        s1 += s2;
        return std::move(s1);
    }

    friend TBasicString operator+(const TBasicString& s1, TBasicString&& s2) Y_WARN_UNUSED_RESULT {
        s2.prepend(s1);