docs!: mark PanelInfo.panel_id as required

Google APIs · copybara-github · commit 4d78f32ab3e3 · 2022-10-12T14:29:57.000-07:00
PiperOrigin-RevId: 480718581
diff --git a/google/cloud/discoveryengine/v1beta/user_event.proto b/google/cloud/discoveryengine/v1beta/user_event.proto
@@ -409,8 +409,8 @@ message DocumentInfo {
 
 // Detailed panel information associated with a user event.
 message PanelInfo {
-  // The panel ID.
-  string panel_id = 2;
+  // Required. The panel ID.
+  string panel_id = 2 [(google.api.field_behavior) = REQUIRED];
 
   // The display name of the panel.
   string display_name = 3;
