Go-gin, context.Done not working as expected

Question

I am trying to use ctx.Done (gin context) to cancel processing request and stop go routine when a user refreshes or exits the page. The code below didn't work, what i do wrong?

respChan := make(chan types.Result)
defer close(respChan)

cCp := c.Copy()

go func() {
    for {
        fmt.Println("check")
        time.Sleep(10000 * time.Millisecond) //long task
        test := []types.ResultTXT{{Txt: "Test Resp"}}
        select {
        case <-cCp.Done():
            fmt.Println("goroutine canceled")
            return
        case respChan <- types.Result{Response: test}:
            fmt.Println("Work end")
            return
        }
    }
}()

select {
case <-c.Done():
    fmt.Println("canceled")
    c.Abort()
    return
case res := <-respChan:
    result := res.Response
    c.HTML(http.StatusOK, "response.html", gin.H{
        "Resp": result,
    })
    return
}

I use gin and go in v. 1.8, but i also tried downgrade (to gin 1.7.7 and use c.Request.Context().Done()) and result is same.