scoped_lock 类
语法
template <class... MutexTypes>
class scoped_lock {
using mutex_type = Mutex; // If MutexTypes... consists of the single type Mutex
explicit scoped_lock(MutexTypes&... m);
explicit scoped_lock(MutexTypes&... m, adopt_lock_t);
~scoped_lock();
scoped_lock(const scoped_lock&) = delete;
scoped_lock& operator=(const scoped_lock&) = delete;
}