...one of the most highly
regarded and expertly designed C++ library projects in the
world. — Herb Sutter and Andrei
Constructor to set a particular expiry time relative to now.
basic_waitable_timer( const executor_type & ex, const duration & expiry_time);
This constructor creates a timer and sets the expiry time.
The I/O executor that the timer will use, by default, to dispatch handlers for any asynchronous operations performed on the timer.
The expiry time to be used for the timer, relative to now.