scp test.txt user@domain:~/pass:='Secret Password'
func main() {
    cmd := exec.Command("scp", "text.txt", "user@domain:~/")        
    stdin, err := cmd.StdinPipe()
    if err = cmd.Start(); err != nil {
        log.Fatalf("failed to start command: %s", err)
    }
    io.WriteString(stdin, "password
")
    if err = cmd.Wait(); err != nil {
    log.Fatalf("command failed: %s", err)
    }
}

If I use this code it is stuck on user@domain's password:

And no file is copied to the remote device.