code: @BetaApi
    public final ListNodeGroupsPagedResponse listNodeGroups(String zone) {
      ListNodeGroupsHttpRequest request =
          ListNodeGroupsHttpRequest.newBuilder().setZone(zone).build();
      return listNodeGroups(request);
    }
docs: Retrieves a list of node groups available to the specified project. Note: use
  nodeGroups.listNodes for more details about each group.
  
  <p>Sample code:
  
  <pre><code>
  try (NodeGroupClient nodeGroupClient = NodeGroupClient.create()) {
  ProjectZoneName zone = ProjectZoneName.of("[PROJECT]", "[ZONE]");
  for (NodeGroup element : nodeGroupClient.listNodeGroups(zone.toString()).iterateAll()) {
  // doThingsWith(element);
  }
  }
  </code></pre>
  
  @param zone The name of the zone for this request.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails