in heatmap/src/heatmap.rs [269:280]
fn new(inner: &'a Heatmap) -> Iter<'a> {
let index = if inner.current.load(Ordering::Relaxed) < (inner.slices.len() - 1) {
inner.current.load(Ordering::Relaxed) + 1
} else {
0
};
Iter {
inner,
index,
visited: 0,
}
}