easy.cpp

std::tuple<std::optional<websocket_client::message>, int>
websocket_client::recv_until(
    std::chrono::steady_clock::time_point const& deadline)
    noexcept
{
    std::tuple<std::optional<
        websocket_client::message>, int> result;
    std::get<1>(result) = recv_until(
        std::get<0>(result), deadline);
    return result;
}

int websocket_client::recv_until(
    std::optional<websocket_client::message>& result,
    std::chrono::steady_clock::time_point const& deadline)
    noexcept
{
    scoped_lock lock(state_lock);

    while (stopping || rx_queue.empty()) {
        if (stopping || cv.wait_until(lock, deadline) ==
                std::cv_status::timeout)
        {
            result = std::nullopt;
            return ERROR_TIMEOUT;
        }
    }

    result = std::move(rx_queue.front());

    rx_queue.pop();

    return ERROR_SUCCESS;
}