class Faraday::Request::Retry

def calculate_retry_interval(retries)
  retry_index = @options.max - retries
  current_interval = @options.interval *
                     (@options.backoff_factor**retry_index)
  current_interval = [current_interval, @options.max_interval].min
  random_interval = rand * @options.interval_randomness.to_f *
                    @options.interval
  current_interval + random_interval
end