if len(s) != 0 {
						args.FieldDelimiter = s
					}
				case "QuoteCharacter":
					if utf8.RuneCountInString(s) > 1 {
						return fmt.Errorf("unsupported QuoteCharacter '%v'", s)
					}
					args.QuoteCharacter = s
				case "QuoteEscapeCharacter":
					switch utf8.RuneCountInString(s) {
					case 0:
						args.QuoteEscapeCharacter = defaultQuoteEscapeCharacter
					case 1:

func (tag Tag) IsEmpty() bool {
	return tag.Key == ""
}

// Validate checks this tag.
func (tag Tag) Validate() error {
	if len(tag.Key) == 0 || utf8.RuneCountInString(tag.Key) > 128 {
		return errInvalidTagKey
	}

	if utf8.RuneCountInString(tag.Value) > 256 {
		return errInvalidTagValue
	}

	return nil

	formattedName := strings.ReplaceAll(strings.Join([]string{
		prefix, table, name,
	}, "_"), ".", "_")

	if ns.IdentifierMaxLength == 0 {
		ns.IdentifierMaxLength = 64
	}

	if utf8.RuneCountInString(formattedName) > ns.IdentifierMaxLength {
		h := sha1.New()
		h.Write([]byte(formattedName))
		bs := h.Sum(nil)

		formattedName = formattedName[0:ns.IdentifierMaxLength-8] + hex.EncodeToString(bs)[:8]
	}

			if got != expect {
				t.Errorf("#%d: %d: expected %q got %q", n, i, expect, got)
			}
		}
		if s.Scan() {
			t.Errorf("#%d: scan ran too long, got %q", n, s.Text())
		}
		testRuneCount := utf8.RuneCountInString(test)
		if runeCount != testRuneCount {
			t.Errorf("#%d: termination expected at %d; got %d", n, testRuneCount, runeCount)
		}
		err := s.Err()
		if err != nil {
			t.Errorf("#%d: %v", n, err)
		}
	}
}