std::unique_lock<Mutex>::swap
From cppreference.com
                    
                                        
                    < cpp | thread | unique lock
                    
                                                            
                    |   void swap( unique_lock& other ) noexcept;  | 
(since C++11) | |
Exchanges the internal states of the lock objects.
Parameters
| other | - | the lock to swap the state with | 
Return value
(none)
Example
| This section is incomplete Reason: no example  | 
See also
|    (C++11)  | 
   specialization of std::swap for unique_lock (function template)  |