code: @BetaApi
    public final ListReferrersInstancesPagedResponse listReferrersInstances(String instance) {
      ListReferrersInstancesHttpRequest request =
          ListReferrersInstancesHttpRequest.newBuilder().setInstance(instance).build();
      return listReferrersInstances(request);
    }
docs: Retrieves the list of referrers to instances contained within the specified zone. For more
  information, read Viewing Referrers to VM Instances.
  
  <p>Sample code:
  
  <pre><code>
  try (InstanceClient instanceClient = InstanceClient.create()) {
  ProjectZoneInstanceName instance = ProjectZoneInstanceName.of("[PROJECT]", "[ZONE]", "[INSTANCE]");
  for (Reference element : instanceClient.listReferrersInstances(instance.toString()).iterateAll()) {
  // doThingsWith(element);
  }
  }
  </code></pre>
  
  @param instance Name of the target instance scoping this request, or '-' if the request should
  span over all instances in the container.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails