func (s *ScreenBuf) WriteString(str string) (int, error) {
	return s.Write([]byte(str))
}
func (s *ScreenBuf) WriteString(str string) (int, error) {
	return s.Write([]byte(str))
}
// WriteString is a convenient function to write a new line passing a string.
// Check ScreenBuf.Write() for a detailed explanation of the function behaviour.