Feat: Add option for get gate with default value

[jenshenneberg]

I'm working on adding a statsig provider for .net and I am facing the same issue as described for GO sdk and Java sdk

Problem
(Copied from statsig-io/java-server-sdk#22)
BooleanEvaluation with default value true cannot fallback to true.
On scenarios such as get gate of non-existing gate, statsig returns false without indication of whether it was successful get gate or some error reason. Therefore, the evaluation will be evaluated to false in this case.

Suggested solution
add:
public static bool CheckGateSync(StatsigUser user, string gateName, bool fallback)

[jenshenneberg]

@tore-statsig : For some reason this feature request has been closed as completed, but I don't think it has been. Would you mind taking a look?

[kenny-statsig]

@jenshenneberg Sorry about that, the issue was auto-closed from our task management integration.
Though we aren't directly supporting a default return value, the new GetFeatureGate API allows you to fallback to a different default value based on the evaluation reason. So in your example, you can check if the evaluation reason is Unrecognized and then choose true. Hope that makes sense.

[jenshenneberg]

@kenny-statsig : Thanks for that. That new API is very helpful and has allowed me to fix the issue in the OpenFeature provider for statsig.