io.go
func WaitForStdin(println ...interface{}) byte {
	if len(println) > 0 {
		fmt.Println(println...)
	}
	buffer := make([]byte, 1)
	os.Stdin.Read(buffer)
	return buffer[0]
}
func WaitForStdin(println ...interface{}) byte {
	if len(println) > 0 {
		fmt.Println(println...)
	}
	buffer := make([]byte, 1)
	os.Stdin.Read(buffer)
	return buffer[0]
}
// WaitForStdin blocks until input is available from os.Stdin.
// The first byte from os.Stdin is returned as result.
// If there are println arguments, then fmt.Println will be
// called with those before reading from os.Stdin.