Undefined headers in successful responses

[Sirach99]

Which SDK version are you using?

19.0.2

What's the issue? / Observed Results

Headers are undefined in successful responses. Like

{
  headers: undefined, 
  ...
}

However, headers are set correctly in errored responses. Like

{
  headers: Object [AxiosHeaders] {'x-app-usage': ...}, 
  ...
}

This has been a frequently requested fix, see:
#87 (comment)
#219
#220

Steps/Sample code to reproduce the issue

1. Make a request. (I called user.getAdAccounts)
2. Log headers
3. Confirm they are undefined in successful responses.

Expected Results:

Headers to contain values such as x-app-usage and x-fb-ads-insights-throttle.
This is very important for throttling API calls.

cc: @stcheng

[Sirach99]

Any updates here, @stcheng?

[stcheng]

@Sirach99 it seems that multiple fixes have been merged. Were you able to determine if the past fixes addressed the issue and debug it to figure out the problem?

[Sirach99]

Hi @stcheng, sorry for the delay. The PR I just added results in displaying the headers as expected.

However, the x-fb-ads-insights-throttle header is still missing for Marketing API calls. Could you please investigate that when you get the chance?

[Sirach99]

Accidentally was not making call to Insights API. Now that I am, I see the x-fb-ads-insights-throttle header.

PR solves header issue I was having 👍