std::chrono::duration<Rep,Period>::operator=
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   duration& operator=( const duration &other ) = default;  | 
(since C++11) | |
Assigns the contents of one duration to another.
Parameters
| other | - |   duration to copy from
 | 
See also
|   constructs new duration  (public member function)  |