code: func AuthTLS(t *tls.Config) client.Option {
  	return func(o *client.Options) {
  		if o.Context == nil {
  			o.Context = context.Background()
  		}
  		o.Context = context.WithValue(o.Context, tlsAuth{}, t)
  	}
  }
docs: // AuthTLS should be used to setup a secure authentication using TLS