add data to assert (#25749)

runtime/src/bucket_map_holder.rs

@@ -72,7 +72,12 @@ impl<T: IndexValue> BucketMapHolder<T> {
         // fetch_add is defined to wrap.
         // That's what we want. 0..255, then back to 0.
         self.age.fetch_add(1, Ordering::Release);
-        assert!(previous >= self.bins); // we should not have increased age before previous age was fully flushed
+        assert!(
+            previous >= self.bins,
+            "previous: {}, bins: {}",
+            previous,
+            self.bins
+        ); // we should not have increased age before previous age was fully flushed
         self.wait_dirty_or_aged.notify_all(); // notify all because we can age scan in parallel
     }