diff --git a/src/scan.rs b/src/scan.rs
index 2a5c58e..be5394d 100644
--- a/src/scan.rs
+++ b/src/scan.rs
@@ -187,6 +187,8 @@ fn jwalk_scan(
 #[cfg(windows)]
 mod win;
 
+// Optimization opportunity: &[&Path] could avoid allocation at some
+// callsites as &mut dyn Iterator<Item = &Path>
 type ScanFn =
     fn(&[&Path]) -> anyhow::Result<batch_channel::Receiver<(IMPath, anyhow::Result<FileInfo>)>>;