class Google::Auth::UserRefreshCredentials

def revoke! options = {}
  c = options[:connection] || Faraday.default_connection
  retry_with_error do
    resp = c.post(REVOKE_TOKEN_URI, token: refresh_token || access_token)
    case resp.status
    when 200
      self.access_token = nil
      self.refresh_token = nil
      self.expires_at = 0
    else
      raise(Signet::AuthorizationError,
            "Unexpected error code #{resp.status}")
    end
  end
end