auto& queue = reg.queue();

queue_reg_t::event_type ev;

while(queue.wait_pop(ev)) {

ev();

}

std::cout << "queue shutdown\n";

std::thread th;

{

auto dtp = queue_t::clock_type::now() + 2500ms;

queue_t queue;

queue.emplace_do([] { std::cout << "done immediately when thread starts\n"; });

queue.set_delay_until(dtp); // <- delays emplace_do events until `dtp`

queue.emplace_do([] { std::cout << "done after delay with events below\n"; });

th = std::thread(event_handler, queue_reg_t(queue)); // or ..., std::ref(queue)

for(int i = 0; i < 10; ++i) {

queue.emplace_do([i] { std::cout << i << '\n'; });

}

queue.emplace_do_in(std::chrono::seconds(0), [] { std::cout << "normal now() + duration, no delay.\n"; });

queue.emplace_do_urgently([] { std::cout << "bypassing the queue\n"; });

std::this_thread::sleep_for(3s);

} // queue.shutdown() and waits for event_handler to finish

th.join();