if (keyObj instanceof final UrlQueue<?> urlQueue) {
            return escapeValue(urlQueue.getUrl());
        }
        if (keyObj instanceof final StatsKeyObject statsKey) {
            return escapeValue(statsKey.getUrl());
        }
        if (keyObj instanceof final String key) {
            return escapeValue(key);
        }
        if (keyObj instanceof final Number key) {

	// escape \ characters
	`\`, `\\`,
	// then escape , and = characters to allow unambiguous parsing of the value in a fieldSelector
	`,`, `\,`,
	`=`, `\=`,
)

// EscapeValue escapes an arbitrary literal string for use as a fieldSelector value
func EscapeValue(s string) string {
	return valueEscaper.Replace(s)
}

// InvalidEscapeSequence indicates an error occurred unescaping a field selector
type InvalidEscapeSequence struct {

		`=`:     `\=`,
		`,`:     `\,`,
		`\`:     `\\`,
		`\=\,\`: `\\\=\\\,\\`,
	}

	for unescapedValue, escapedValue := range testcases {
		actualEscaped := EscapeValue(unescapedValue)
		if actualEscaped != escapedValue {
			t.Errorf("EscapeValue(%s): expected %s, got %s", unescapedValue, escapedValue, actualEscaped)
		}

		actualUnescaped, err := UnescapeValue(escapedValue)
		if err != nil {