[Feature] Microsoft.Toolkit lacks nullability annotations (and others)

[Sergio0694]

Overview

I was going through the codebase for the main Microsoft.Toolkit package while reading #3315 and noticed the package has a few inconsistencies and issues now compared to the other .NET Standard packages (especially Mvvm and HighPerformance):

• It lacks the nullability annotations
• It lacks some extra annotations in general (eg. [Pure] when needed)
• Some methods have unclear/inconsistent behavior. For instance, some string extensions are fine with null parameters and in that case just return null. Some are fine with null inputs but always return non null. Some just crash. The behavior should just be made consistent with all (I'd say they should just accept a non nullable string and crash if one is received).

Describe the solution

I can make a PR to address these various points if that's fine for you guys.
@azchohfi if it makes things easier, should I wait for yours or some other PR to be merged in first (to avoid conflicts) or is that not important and I can just branch off of master when I have some time and start working on this?

P.S. @michael-hawker opened an issue first this time 🙈

[ghost]

Hello, 'Sergio0694! Thanks for submitting a new feature request. I've automatically added a vote 👍 reaction to help get things started. Other community members can vote to help us prioritize this feature in the future!

[michael-hawker]

@Sergio0694 you completed this, eh? We can move this back to 7.0 and close?

[Sergio0694]

Yup, I've added the annotations and enabled nullable types right in the .csproj for the whole package, we're good! 😄