type Queue interface {
   AddMessageToQueue(msg QueueMessage)
}

type QueueMessage interface {
   ToSQSFormat() ...
   ToAzureFormat() ...
   ...
}

type QueueMessage interface {
    Format() []byte
}

type SQSFormat struct {
    ID string
    Payload string
    At time.Time
}

func (s SQSFormat) Format() []byte {
    return []byte(fmt.Sprintf("%+v", s))
}

type AzureFormat struct {
    Channel string
    Payload string
}

func (a AzureFormat) Format() []byte {
    return []byte(fmt.Sprintf("%+v", a))
}

type Queue interface {
    AddMessageToQueue(msg QueueMessage)
    ProcessMessages()
}

type MessageQueue struct{
    Messages []QueueMessage
}

func (m *MessageQueue) AddMessageToQueue(msg QueueMessage) {
    if m.Messages == nil {
        m.Messages = []QueueMessage{}
    }
    m.Messages = append(m.Messages, msg)
}

func (m *MessageQueue) ProcessMessages() {
    for _, msg := range m.Messages {
        fmt.Println(string(msg.Format())) // <- will print the formatted message based on the concrete type specified
    }
}

func main() {
    var mq Queue = &MessageQueue{}
    var SQSMsg = SQSFormat{
        ID: "id",
        Payload: "something happened",
        At: time.Now(),
    }
    mq.AddMessageToQueue(SQSMsg)

    var azureMsg = AzureFormat{
        Channel: "channel",
        Payload: "something happened",
    }
    mq.AddMessageToQueue(azureMsg)

    mq.ProcessMessages()
}