std::reference_wrapper<T>::operator=
来自cppreference.com
                    
                                        
                    < cpp | utility | functional | reference wrapper
                    
                                                            
                    |   reference_wrapper& operator=( const reference_wrapper& other ) noexcept;  | 
 (C++11 起)  (C++20 前)  | 
|
|   constexpr reference_wrapper& operator=( const reference_wrapper& other ) noexcept;  | 
(C++20 起) | |
复制赋值运算符。丢弃当前引用,并存储到 other.get() 的引用。
参数
| other | - |   要复制的 reference_wrapper
 | 
返回值
*this