Fix build, return value must be used.

Release-Notes: skip
Change-Id: I5288f9b34ac1b3ef9ce329f12f844d009dce695f
diff --git a/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java b/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
index f5a4862..9ad1744 100644
--- a/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
+++ b/java/com/google/gerrit/server/api/changes/ChangeApiImpl.java
@@ -580,7 +580,7 @@
   @Override
   public void setCustomKeyedValues(CustomKeyedValuesInput input) throws RestApiException {
     try {
-      postCustomKeyedValues.apply(change, input);
+      var unused = postCustomKeyedValues.apply(change, input);
     } catch (Exception e) {
       throw asRestApiException("Cannot post custom keyed values", e);
     }