Serialize base properties first

I’m pretty sure this has been asked before but I can’t seem to track it down. Is there a way to force the JSON serializer to output base properties before the child ones?

For example:
public class Foo { public string A {get;set;} }
public class Bar : Foo { public string B {get;set;} }

In the output I’d prefer to get A before B.

Is that configurable?

No this behavior isn’t configurable.