rename return fields for clarity

logmetric.py

@@ -149,6 +149,6 @@ class LogMetric(evaluate.Metric):
         logmetric_duration = f" {t_after_logmetric - t_before_logmetric:0.10f}"
 
         return {
-            "timestamp_score": timestamp_score,
-            "logmetric_duration": logmetric_duration,
+            "score": timestamp_score,
+            "duration": logmetric_duration,
         }