diff --git a/CHANGELOG_PENDING.md b/CHANGELOG_PENDING.md
index 8a1927a39ca..44e05de29f2 100644
--- a/CHANGELOG_PENDING.md
+++ b/CHANGELOG_PENDING.md
@@ -3,3 +3,5 @@
 ### SDK Enhancements
 
 ### SDK Bugs
+* `codegen`: Export event stream constructor for easier mocking ([#3473](https://github.com/aws/aws-sdk-go/pull/3473))
+  * Fixes [#3412](https://github.com/aws/aws-sdk-go/issues/3412) by exporting the operation's EventStream type's constructor function so it can be used to fully initialize fully when mocking out behavior for API operations with event streams.