Iterate list_of_data once in writelines per review

Author: moktamd

Lib/asyncio/selector_events.py

@@ -1194,8 +1194,11 @@ def writelines(self, list_of_data):
             self._conn_lost += 1
             return
 
-        self._buffer_size += sum(len(data) for data in list_of_data)
-        self._buffer.extend([memoryview(data) for data in list_of_data])
+        views = []
+        for data in list_of_data:
+            views.append(memoryview(data))
+            self._buffer_size += len(data)
+        self._buffer.extend(views)
         self._write_ready()
         # If the entire buffer couldn't be written, register a write handler
         if self._buffer: