Added ProviderStateChanged event to ProviderManager

[shweaver-MSFT]

Fixes #16

PR Type

What kind of change does this PR introduce?

• Feature

What is the current behavior?

Currently, the ProviderUpdated event is used to check when any changes occur to the GlobalProvider instance in ProviderManager. This includes setting the IProvider instance or in response to authentication state changes.

ProviderManager.Instance.ProviderUpdated += OnProviderUpdated;

void OnProviderUpdated(object sender, ProviderUpdatedEventArgs e)
{
    if (e.Reason == ProviderManagerChangedState.ProviderChanged)
    {
        // The global provider instance was set.
    }

    if (e.Reason == ProviderManagerChangedState.ProviderStateChanged)
    {
        // The state of the global provider instance has changed.
    }
}

What is the new behavior?

I propose changing the ProviderUpdated event to only emit when the GlobalProvider instance itself is changed/set, while also introducing a new ProviderStateChanged event which should fire on provider state changes.

ProviderManager.Instance.ProviderUpdated += OnProviderUpdated;
ProviderManager.Instance.ProviderStateChanged += OnProviderStateChanged;

void OnProviderUpdated(object sender, IProvider provider)
{
    // The GlobalProvider instance has been set.
}

void OnProviderStateChanged(object sender, ProviderStateChangedEventArgs e)
{
    // The state of the GlobalProvider instance has changed.
}

The following classes are also no longer required and have been removed:

• ProviderUpdatedEventArgs
• ProviderManagerChangedState

PR Checklist

Please check if your PR fulfills the following requirements:

• Tested code with current supported SDKs
• Sample in sample app has been added / updated (for bug fixes / features)
  • Icon has been created (if new sample) following the Thumbnail Style Guide and templates
• Tests for the changes have been added (for bug fixes / features) (if applicable)
• Header has been added to all new source files (run build/UpdateHeaders.bat)
• Contains NO breaking changes

Other information

[ghost]

Thanks shweaver-MSFT for opening a Pull Request! The reviewers will test the PR and highlight if there is any merge conflict or changes required. If the PR is approved we will proceed to merge the pull request 🙌