429 Response Handling Fails on Missing retry-after Header

[ydag]

When processing an HTTP response with a 429 (Too Many Requests) status code, the SDK's internal handleResponse function attempts to throw a TooManyRequestsException. This exception expects a retry-after header to set the _retryAfter property. However, if the response lacks the retry-after header, the SDK generates a Null check operator used on a null value exception due to the null assertion on the retry-after header value. This behaviour might lead to unexpected errors for developers using the SDK.

Steps to Reproduce:

• Trigger a request resulting in a 429 status code response without the retry-after header using the SDK's public-facing functions.
• Observe the "Null check operator used on a null value" exception.

Expected Behavior:
The SDK should handle a 429 status code, regardless of the retry-after header's presence or absence.

Actual Behavior:
The SDK raises a null assertion error due to the absent retry-after header.

Suggested Fix:

• Make the _retryAfter property nullable and manage cases where the retry-after header is not present.