func (w *HTMLWriter) flushPhases() {
	phaseLen := len(w.pendingPhases)
	if phaseLen == 0 {
		return
	}
	phases := strings.Join(w.pendingPhases, "  +  ")
	w.WriteMultiTitleColumn(
		phases,
		w.pendingTitles,
		fmt.Sprintf("hash-%x", w.prevHash),
		w.Func.HTML(w.pendingPhases[phaseLen-1], w.dot),
	)
	w.pendingPhases = w.pendingPhases[:0]
	w.pendingTitles = w.pendingTitles[:0]
}