Function window_count 

pub fn window_count(
    core: &Core,
    binding: &Arc<dyn ProducerBinding>,
    source: NodeId,
    count: usize,
) -> NodeId

Like window but closes window every count DATA items.

• On activation: create first window, emit it.
• Source DATA: forward to current window + increment counter. When counter hits count, complete current window, create new one, emit it, reset counter.
• Source COMPLETE: complete current window (even if < count items), complete self.
• Source ERROR: error current window, error self.

Panics

Panics if count is 0.