Merge branch 'stable-3.1'

* stable-3.1:
  Enable asynchronous message send for kafka producer
  Add {Create|Delete}ChangeUsingMultiGerrits scenarios

Change-Id: Id3e0a8fdffa2651a2250feffecb29b52a0b24131
diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/index/ChangeCheckerImpl.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/index/ChangeCheckerImpl.java
index 32b8af3..15b1e09 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/index/ChangeCheckerImpl.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/multisite/index/ChangeCheckerImpl.java
@@ -79,7 +79,7 @@
   @Override
   public Optional<ChangeNotes> getChangeNotes() {
     try (ManualRequestContext ctx = oneOffReqCtx.open()) {
-      this.changeNotes = Optional.ofNullable(changeFinder.findOne(changeId));
+      this.changeNotes = changeFinder.findOne(changeId);
       return changeNotes;
     }
   }