object's event processing loop until a specified time.
template< typename Clock, typename Duration> std::size_t run_until( const chrono::time_point< Clock, Duration > & abs_time);
run_until() function blocks until all work has finished
and there are no more handlers to be dispatched, until the
has been stopped, or until the specified time has been reached.
The time point until which the call may block.
The number of handlers that were executed.