Method pop_front

code/common/src/Utils/ThreadUtils.h:33–38

    }

    void pop_front() {
        std::unique_lock<std::mutex> mlock(mtx);
        while (q.empty())
            cond.wait(mlock);
        q.pop();
    }

    void push_back(const T &item) {
        std::unique_lock<std::mutex> mlock(mtx);