[PR #9765/e06dec37 backport][3.10] Avoid duplicate len calls in StreamReader.feed_data (#9768)

Co-authored-by: J. Nick Koston <[email protected]>

Author: patchback[bot]

aiohttp/streams.py

@@ -245,9 +245,10 @@ def feed_data(self, data: bytes, size: int = 0) -> None:
         if not data:
             return
 
-        self._size += len(data)
+        data_len = len(data)
+        self._size += data_len
         self._buffer.append(data)
-        self.total_bytes += len(data)
+        self.total_bytes += data_len
 
         waiter = self._waiter
         if waiter is not None: