return s, false, nil
}

var rfc2047Decoder = mime.WordDecoder{
	CharsetReader: func(charset string, input io.Reader) (io.Reader, error) {
		return nil, charsetError(charset)
	},
}

type charsetError string

func (e charsetError) Error() string {
	return fmt.Sprintf("charset not supported: %q", string(e))
}

// isAtext reports whether r is an RFC 5322 atext character.