docs: @BetaApi
    public final Operation insertNodeGroup(
        Integer initialNodeCount, ProjectZoneName zone, NodeGroup nodeGroupResource) {
  
      InsertNodeGroupHttpRequest request =
          InsertNodeGroupHttpRequest.newBuilder()
              .setInitialNodeCount(initialNodeCount)
              .setZone(zone == null ? null : zone.toString())
              .setNodeGroupResource(nodeGroupResource)
              .build();
      return insertNodeGroup(request);
    }