improve performance of writing past the end of the file for cStringIO
(http://bugs.python.org/issue10045)
diff --git a/Misc/NEWS b/Misc/NEWS
index 613afd9..d86f34f 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -48,6 +48,9 @@
 Library
 -------
 
+- Issue #10045: Improved performance when writing after seeking past the
+  end of the "file" in cStringIO.
+
 - Issue #9948: Fixed problem of losing filename case information.
 
 - Issue #9437: Fix building C extensions with non-default LDFLAGS.