Cannot read the response body inside the Backoff function (I think)

[paprikati]

From my testing, if you try to read the response body in the Backoff function, you get an error:

http2: response body closed

Is there any way to access the response body within that function? (In our case, the 'retry after' information is in the body of the response)

The code I'm testing is:

func newClient() http.Client {
	retryClient := retryablehttp.NewClient()
	retryClient.RetryMax = 3
	retryClient.Backoff = LisaTest
        return retryClient
}

func TestBackoff(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration {
	if resp != nil {
		var target map[string]interface{}
		err := json.NewDecoder(resp.Body).Decode(&target)
		spew.Dump(err)
		spew.Dump(target)
	}
	return 1 * time.Second
}

I could well be being thick here - would love to know if we're missing something simple (or it's some part of our implementation that I've missed)!