Update pkg/cache/v3/resource.go

Co-authored-by: Antoine Tollenaere <atollena@gmail.com>
Signed-off-by: Valerian Roche <valerian.roche@datadoghq.com>

pkg/cache/v3/resource.go

@@ -102,8 +102,9 @@ func GetResourceName(res types.Resource) string {
 func ResourceRequiresFullStateInSotw(typeURL resource.Type) bool {
 	// From https://www.envoyproxy.io/docs/envoy/v1.28.0/api-docs/xds_protocol#grouping-resources-into-responses,
 	// when using sotw the control-plane MUST return all requested resources (or simply all if wildcard)
-	// for some types. This is relied on by xds-grpc which is explicitly requesting clusters but expect
-	// to receive all existing resources
+	// for some types. This is relied on by xds-grpc which is explicitly requesting clusters and listeners
+	// but expects to receive all existing resources for those types. Missing clusters or listeners are 
+	// considered deleted.
 	switch typeURL {
 	case resource.ClusterType:
 		return true