std::reference_wrapper<T>::get, std::reference_wrapper<T>::operator T&
From cppreference.com
                    
                                        
                    < cpp | utility | functional | reference wrapper
                    
                                                            
                    |   operator T& () const noexcept;  | 
(since C++11) | |
|   T& get() const noexcept;  | 
(since C++11) | |
Returns the stored reference.
Parameters
(none)
Return value
The stored reference.
See also
|    calls the stored function   (public member function)  |