Function interval_delayed_by_at_least 

pub fn interval_delayed_by_at_least(
    delay: Duration,
    period: Duration,
) -> Result<IntervalAfter, IntervalError>

Creates a timer that emits events periodically, starting after at least delay.

Returns an error if period is zero.

See interval_delayed_by for details. The events are guaranteed to be emitted no sooner than the expected instants.