docs: @BetaApi(
        "The surface for long-running operations is not stable yet and may change in the future.")
    public final OperationFuture<Cluster, ClusterOperationMetadata> createClusterAsync(
        String projectId, String region, Cluster cluster) {
  
      CreateClusterRequest request =
          CreateClusterRequest.newBuilder()
              .setProjectId(projectId)
              .setRegion(region)
              .setCluster(cluster)
              .build();
      return createClusterAsync(request);
    }