What is the best approach to implement polymorphic against single Subscription Resolver

[cfeng-wm]

Hello Hotchocolate team,
I am new to Hotchocalate and graphql, recently I am working on a microservice project adopted this technique, I have some questions,

1. does hotchocalate support single subscription resolver method return different response type? (we intend to reduce connection from client side)
   We had implemented unionType with multiple entity types, but one resolver method only allow one Output Type,
2. Could you advise if Subscription in Hotchocalate supports Output type based on Interface or abstract class? I tried interface , but
   got InvalidMessageType when called sender.sendAsync( topic, object implanted the interface mentioned above)
   Or my understand on interfaceType is completely wrong?

Thank you in advance,

Charles