}

func writeSentinel(out io.Writer) {
	fmt.Fprintf(out, "sentinel %x\n", sentinel())
}

// formatStack formats a stack of PC values using the symbol table,
// redacting information that cannot be relied upon in the test.
func formatStack(pcs []uintptr) string {
	// When debugging, show file/line/content of files other than this one.
	const debug = false

	var buf strings.Builder