// By this way, even if istioctl cannot access a specific `istiod` instance directly,
// `istioctl` can access the debug endpoint.
// If `all` is true, `queryDebugSynczViaAgents` iterates all the pod having a proxy
// except the pods of which status information is already queried.
func queryDebugSynczViaAgents(all bool, dr *discovery.DiscoveryRequest, istioNamespace string, kubeClient kube.CLIClient,