如何在Go中为这些类型建模

Question

I have multiple types like this:

type QueryMessage struct {
    Header MessageHeader
    Type   MessageType
    Query  SqlQuery
}

type UpdateMessage struct {
    Header  MessageHeader
    Type    MessageType
    OldData map[string]interface{}
    NewData map[string]interface{}
}

type InsertMessage struct {
    Header MessageHeader
    Type   MessageType
    Data   map[string]interface{}
}

They all have two properties in common, Header and Type. In the end I need to aggregate them into an array of generic messages. At the moment my Message interface looks like this:

type Message interface {}

So what I basically do is something like this (casting them all to Message interface):

q := QueryMessage{ ... }
u := UpdateMessage{ ... }
i := InsertMessage{ ... }
allMessages := [3]Message { Message(q), Message(u), Message(i), }

This works, but it loses all the type information and I would like to be able to still expose Header and Type from the Message type (so that client code theoretically could cast the Message based on the Type back to it's original type.

How can this be done? I couldn't figure out a proper way, interfaces can't have properties and if I make Message a struct, Go doesn't allow me to cast e. g. a QueryMessage to a Message anymore.