code: func TokenSourceWrapTransport(ts oauth2.TokenSource) func(http.RoundTripper) http.RoundTripper {
  	return func(rt http.RoundTripper) http.RoundTripper {
  		return &tokenSourceTransport{
  			base: rt,
  			ort: &oauth2.Transport{
  				Source: ts,
  				Base:   rt,
  			},
  		}
  	}
  }
docs: // TokenSourceWrapTransport returns a WrapTransport that injects bearer tokens
  // authentication from an oauth2.TokenSource.