public static extern IntPtr add_notification_callback(SubscriptionHandle subscription, IntPtr managedSubscriptionHandle, SubscriptionCallbackDelegate callback, out NativeException ex);
public SubscriptionTokenHandle AddNotificationCallback(IntPtr managedObjectHandle, SubscriptionCallbackDelegate callback)
{
var result = NativeMethods.add_notification_callback(this, managedObjectHandle, callback, out var ex);
ex.ThrowIfNecessary();
return(new SubscriptionTokenHandle(this, result));
}