Run the io_context
object's
event processing loop for a specified duration to execute at most one handler.
template< typename Rep, typename Period> std::size_t run_one_for( const chrono::duration< Rep, Period > & rel_time);
The run_one_for()
function blocks until one handler has been
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.