Fixes issue #6838: use a list to accumulate the value instead of repeatedly concatenating strings.
diff --git a/Misc/NEWS b/Misc/NEWS
index 000f2c7..80c636f 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -50,6 +50,11 @@
 Library
 -------
 
+- Issue #6838: Use a list to accumulate the value instead of
+  repeatedly concatenating strings in http.client's
+  HTTPResponse._read_chunked providing a significant speed increase
+  when downloading large files servend with a Transfer-Encoding of 'chunked'.
+
 - Have importlib raise ImportError if None is found in sys.modules for a
   module.