|  | 
           
Run the io_context object's event processing
          loop for a specified duration.
        
template< typename Rep, typename Period> std::size_t run_for( const chrono::duration< Rep, Period > & rel_time);
          The run_for()
          function blocks until all work has finished and there are no more handlers
          to be dispatched, until the io_context has been stopped, or
          until the specified duration has elapsed.
        
The duration for which the call may block.
The number of handlers that were executed.