Use SmartEnumValue.When().Then() with async

[stevenvolckaert]

I couldn't find this in the issues or documentation: Is it allowed to switch on SmartEnum values using the .When().Then() pattern, when the Then() action delegate is asynchronous?

For example, in a FastEndpoints endpoint I currently have the following:

public override Task HandleAsync(
    ListAddressRequest request,
    CancellationToken cancellationToken)
{
    ThrowArgumentNullException.If.Null(request);

    var country = Country.FromValue(request.Address.Country);

    country
        .When(Country.Belgium).Then(async () =>
        {
            var listResult = await this.ListBelgiumAddressesAsync(request, cancellationToken);
            await this.SendResultAsync(listResult);
        })
        .Default(async () =>
        {
            var errorResult = Result.Error(new ErrorList
            (
                ErrorMessages: [$"Country '{country.Value}' is not supported."]
            ));
            await this.SendResultAsync(errorResult);
        });

    return Task.CompletedTask;
}

(Country is SmartEnum<Country, string> where each value is the country code.)

Both action delegates passed to Then() and Default() are async, and the code compiles. But will this execute correctly?