TEZ-3855 addendum. Allow vertex manager to send event to processor (zhiyuany)
diff --git a/tez-api/src/main/java/org/apache/tez/runtime/api/events/CustomProcessorEvent.java b/tez-api/src/main/java/org/apache/tez/runtime/api/events/CustomProcessorEvent.java
index 9cfb02e..7d84a1d 100644
--- a/tez-api/src/main/java/org/apache/tez/runtime/api/events/CustomProcessorEvent.java
+++ b/tez-api/src/main/java/org/apache/tez/runtime/api/events/CustomProcessorEvent.java
@@ -51,7 +51,7 @@
   }
 
   public ByteBuffer getPayload() {
-    return payload;
+    return payload.asReadOnlyBuffer();
   }
 
   @Private