code: func (ctl *taskController) GetClient(ctx context.Context, opts ...auth.RPCOption) (*http.Client, error) {
  	opts = append(opts, auth.WithProject(ctl.saved.GetProjectID()))
  	t, err := auth.GetRPCTransport(ctx, auth.AsProject, opts...)
  	if err != nil {
  		return nil, err
  	}
  	return &http.Client{Transport: t}, nil
  }
docs: // GetClient is part of task.Controller interface