if !atEOF {
				return 0, nil, nil
			}
			// If we have reached the end, return the last token.
			return 0, data, bufio.ErrFinalToken
		}
		// If the token is "STOP", stop the scanning and ignore the rest.
		if string(data[:i]) == "STOP" {
			return i + 1, nil, bufio.ErrFinalToken
		}
		// Otherwise, return the token before the comma.
		return i + 1, data[:i], nil
	}
	const input = "1,2,STOP,4,"