Handle 429 and 5xx HTTP errors

[fathyb]

Currently, our retry implementations only retries on network errors, it doesn't handle HTTP errors.

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Ref: LIB-515

[f2prateek]

I think we want to not retry on 4xx errors (except 429, where we should retry).

From the guidelines:

In general, the retry strategy should be kept simple:

1. Retry network errors (socket timed out, etc.)
2. Retry server errors (HTTP 5xx)
3. Do not retry client errors (HTTP 4xx)
  1. Except HTTP 429.

[fathyb]

thanks @f2prateek! it's fixed

[f2prateek]

Thanks. LGTM! Can you write up a CC ticket?

[fathyb]

@f2prateek here is it : https://segment.atlassian.net/browse/CC-1424