in src/max_rows.rs [51:58]
fn with_new_children(
self: std::sync::Arc<Self>,
children: Vec<std::sync::Arc<dyn ExecutionPlan>>,
) -> Result<std::sync::Arc<dyn ExecutionPlan>> {
// TODO: generalize this
assert_eq!(children.len(), 1);
Ok(Arc::new(Self::new(children[0].clone(), self.max_rows)))
}