Method try_push

async_simple/util/Queue.h:48–57

    }

    bool try_push(const T &item) {
        {
            std::unique_lock lock(_mutex, std::try_to_lock);
            if (!lock)
                return false;
            _queue.push(item);
        }
        _cond.notify_one();
        return true;
    }

    bool pop(T &item) {
        std::unique_lock lock(_mutex);