diff --git a/src/elo.rs b/src/elo.rs
index 1fefe4e..a3ee1a2 100644
--- a/src/elo.rs
+++ b/src/elo.rs
@@ -145,6 +145,9 @@ impl PlayerArena {
                     .expect("invalid ProgressStyle"),
             )
             .map(|((i, j), (p1, p2))| (i, j, Self::play_two_inner(p1, p2)))
+            // TODO! is there some way in rayon to allow `self.process_outcome` to be run on the main thread
+            // as soon as Self::play_two_inner completes? This would allow maybe a live leaderboard to be displayed
+            // while players are playing
             .collect::<Vec<_>>()
             // collect and process the outcomes of all the games
             .into_iter()