From bd8ef0c6846c5b9ad1abda05c7b5fccea68db1f7 Mon Sep 17 00:00:00 2001
From: David Turner <david.turner@elastic.co>
Date: Sat, 21 Aug 2021 10:41:55 +0100
Subject: [PATCH] Comment on NOT_SET

---
 .../elasticsearch/cluster/ClusterStatePublicationEvent.java    | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/server/src/main/java/org/elasticsearch/cluster/ClusterStatePublicationEvent.java b/server/src/main/java/org/elasticsearch/cluster/ClusterStatePublicationEvent.java
index 0ff610410c9e0..e306787dfbb4a 100644
--- a/server/src/main/java/org/elasticsearch/cluster/ClusterStatePublicationEvent.java
+++ b/server/src/main/java/org/elasticsearch/cluster/ClusterStatePublicationEvent.java
@@ -14,6 +14,9 @@
  */
 public class ClusterStatePublicationEvent {
 
+    /**
+     * Sentinel value so that we can assert each field is set once and only once on each successful event, and at most once on each failure.
+     */
     private static final long NOT_SET = -1L;
 
     private final String summary;