feat: use Meziantou.Polyfill to allow for nullable static analysis in HttpClientRequestResult

[JMolenkamp]

The library does not contain attributes to be used by the compiler for static nullable analysis.
This results in warnings even though HttpClientRequestResult<TData>.HasData was already evaluated to be true:

There are probably more classes where this is useful, but this is where i encountered it.

[perkops]

Hi @JMolenkamp,

Thank you for the contribution.

However, when running the pipeline, we can see that something in the Polyfill library conflicts with the existing code-base:

https://github.com/atc-net/atc/actions/runs/9488032839/job/26168150710?pr=319

"CSC : error CA1708: Names of 'Types' and 'Helpers, Helpers, Helpers' should differ by more than case (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1708)"

However, we cannot currently pin-point where the error stems from - Sure we can set the warning to none in an .editorconfig, but would not currently be sure what implications this would have.

Do you have any experience with that error when adding the Polyfill library from Meziantou?

[JMolenkamp]

Hi @perkops,

I know of the possibility to declare the attributes for nullable analysis in a code base. While once again searching how to do this, i found this blog post by meziantou and a mention of his Polyfill library. I reckoned this would be easier. Since you were already using a meziantou package, i thought it might be acceptable to add this reference, not knowing it would fail the pipeline.

I do not have any experience with this library yet, but I will try to resolve the issues somewhere in the coming days. According to the github page some customization is possible.

Searching through the Polyfill library (link), four classes named Helpers are found. However, all these classes are marked with the file modifier, so I would not expect them to cause any problems, since they are not accessible from anywhere except for the file they are declared in.

However, at first glance, I cannot find anything named Types.