Retry logs

- [X] I have checked that the [SDK documentation][sdk-docs] doesn't solve my issue.
- [X] I have checked that the [API documentation][api-docs] doesn't solve my issue.
- [X] I have searched the [Box Developer Forums][dev-forums] and my issue isn't already reported (or if it has been reported, I have attached a link to it, for reference).
- [X] I have searched [Issues in this repo][github-repo] and my issue isn't already reported.

### Description of the Issue
The box SDK natively handles retry attempts and there seems to be no way to get the retry attempt logs.
Is there a way to catch the retry logs from the sdk?
I would like to capture the logs to prevent retry events from happening in the future.

### Steps to Reproduce
Trigger exponential backoff scenario such as 429, 500, etc
https://github.com/box/box-windows-sdk-v2/blob/ee1900636999f01fc914dcb0373a275325fdfc98/Box.V2/Request/HttpRequestHandler.cs#L80

### Expected Behavior
Catch retry attempts

### Error Message, Including Stack Trace

### Screenshots

### Versions Used
.Net SDK: latest version
Windows 10

[sdk-docs]: ./docs
[api-docs]: https://developer.box.com/docs
[dev-forums]: https://community.box.com/t5/Platform-and-Development-Forum/bd-p/DeveloperForum
[github-repo]: https://github.com/box/box-windows-sdk-v2/search?type=Issues

Start with Box.V2/Request/HttpRequestHandler.cs around line 80, where the issue says retry handling occurs. Trace how 429 and 500 responses enter exponential backoff and identify what retry information is currently exposed. Done means retry attempts can be captured by SDK consumers; verify with a scenario that triggers 429 or 500.

Written by the indexing model from the issue text.