code: func WithNamespace(s string) source.Option {
  	return func(o *source.Options) {
  		if o.Context == nil {
  			o.Context = context.Background()
  		}
  		o.Context = context.WithValue(o.Context, namespaceKey{}, s)
  	}
  }
docs: // WithNamespace is an option to add namespace of configmap