code: func withAccessClientMiddleware(c *router.Context, next router.Handler) {
  	client, err := common.NewAccessClient(c.Context)
  	if err != nil {
  		ErrorHandler(c, err)
  		return
  	}
  	c.Context = common.WithAccessClient(c.Context, client)
  	next(c)
  }
docs: // withAccessClientMiddleware is a middleware that installs a prod buildbucket
  // access API client into the context.
  //
  // This middleware depends on auth middleware in order to generate the access
  // client, so it must be called after the auth middleware is installed.