每个请求的会话ID都不相同

On Heroku, I am using the sessions within the Iris framework for Go. Each time I make a request to the server from the browser page, the session ID is different.

My code:

When the application starts (global scope)

var appSession = sessions.New(sessions.Config{Cookie: "cookiesessionid"})

Incoming request

func post Request(ctx iris.Context) {

    sess := appSession.Start(ctx)
    sess := appSession.Start(ctx)
    fmt.Printf("%#v", sess)
}

Every time I run the request the session identifier revealed by the print statement, is different. Why would this be?

For what it's worth - the page is running out of an iframe.