code: func (b *Builder) URL(httpAttemptCount int, urls ...*url.URL) *Builder {
  	for _, u := range urls {
  		b.paths = append(b.paths, &URLVisitor{
  			URL:              u,
  			StreamVisitor:    NewStreamVisitor(nil, b.mapper, u.String(), b.schema),
  			HttpAttemptCount: httpAttemptCount,
  		})
  	}
  	return b
  }
docs: // URL accepts a number of URLs directly.