Function interval 

pub fn interval(
    core: &Core,
    binding: &Arc<dyn ProducerBinding>,
    period_ms: u64,
) -> NodeId

Source that emits a monotonically increasing counter (1, 2, 3, …) every period_ms milliseconds. Counter starts at 1 (not 0) because HandleId(0) is the NO_HANDLE sentinel. Resubscribable: counter resets on deactivation + reactivation.

The emitted values use raw HandleId::new(counter). Bindings should register these as integer handles.