diff --git a/crates/coremem/src/driver.rs b/crates/coremem/src/driver.rs
index d09da0e..3af94c3 100644
--- a/crates/coremem/src/driver.rs
+++ b/crates/coremem/src/driver.rs
@@ -22,6 +22,7 @@ pub struct Driver<S> {
     // TODO: use Rayon's thread pool?
     render_pool: ThreadPool,
     render_channel: (SyncSender<()>, Receiver<()>),
+    // TODO: split out into a Diagnostics struct
     time_spent_stepping: Duration,
     time_spent_on_stimuli: Duration,
     time_spent_prepping_render: Duration,