NBJSONRPC050: Use IClientProxy for marshalable interface checks

Property	Value
ID	NBJSONRPC050
Category	Usage
Severity	Warning

Use the generated interface-level Is(Type) or As<T> extensions when checking or converting between two RpcMarshalableAttribute-annotated interfaces. These APIs query the capabilities advertised by a generated proxy, while retaining ordinary type-check behavior for user-defined objects.

// NBJSONRPC050
if (value is IOptionalFeature)
{
}

Use value.As<IOptionalFeature>() to convert a proxy, or value.Is(typeof(IOptionalFeature)) to test its advertised capabilities.