Optimizations

Author: gwaramadze

quixstreams/dataframe/windows/time_based.py

@@ -271,7 +271,7 @@ def process_window(
         # Combine triggered windows with time-expired windows
         all_expired_windows = triggered_windows + list(expired_windows)
 
-        return updated_windows, iter(all_expired_windows)
+        return updated_windows, all_expired_windows
 
     def expire_by_partition(
         self,