Method Add

tests/test_class_sh_trampoline_shared_from_this.cpp:46–51

    explicit SftSharedPtrStash(int ser_no) : ser_no{ser_no} {}
    void Clear() { stash.clear(); }
    void Add(const std::shared_ptr<Sft> &obj) {
        if (!obj->history.empty()) {
            obj->history += "_Stash" + std::to_string(ser_no) + "Add";
        }
        stash.push_back(obj);
    }
    void AddSharedFromThis(Sft *obj) {
        auto sft = obj->shared_from_this();
        if (!sft->history.empty()) {