Method on_tracker_accept

cpp/src/context_test.cpp:137–142

    }

    void on_tracker_accept(proton::tracker &t) override {
        std::string data = "tracker-user-data";
        // Set user context 'data' on tracker.
        t.user_data(&data);
        ASSERT_EQUAL(&data, t.user_data());
    }
};

int test_user_context() {