Macro at 

macro_rules! at {
    ( $inst:expr, $($x:tt)+ ) => { ... };
}

At the given Instant, perform an actor call or inline code

The syntax of the calls is identical to lazy!, but with an Instant argument first. Returns a FixedTimerKey which can be used to delete the timer if necessary using Core::timer_del. See also after!.

at!(instant, ...args-as-for-lazy-macro...);

Implemented using Core::timer_add, Actor::apply and Actor::apply_prep.