code: @BetaApi
    public final ListNetworkEndpointGroupsPagedResponse listNetworkEndpointGroups(String zone) {
      ListNetworkEndpointGroupsHttpRequest request =
          ListNetworkEndpointGroupsHttpRequest.newBuilder().setZone(zone).build();
      return listNetworkEndpointGroups(request);
    }
docs: Retrieves the list of network endpoint groups that are located in the specified project and
  zone.
  
  <p>Sample code:
  
  <pre><code>
  try (NetworkEndpointGroupClient networkEndpointGroupClient = NetworkEndpointGroupClient.create()) {
  ProjectZoneName zone = ProjectZoneName.of("[PROJECT]", "[ZONE]");
  for (NetworkEndpointGroup element : networkEndpointGroupClient.listNetworkEndpointGroups(zone.toString()).iterateAll()) {
  // doThingsWith(element);
  }
  }
  </code></pre>
  
  @param zone The name of the zone where the network endpoint group is located. It should comply
  with RFC1035.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails