/**
     * Returns true if computeFreshnessLifetime used a heuristic. If we used a heuristic to serve a
     * cached response older than 24 hours, we are required to attach a warning.
     */
    private fun isFreshnessLifetimeHeuristic(): Boolean = cacheResponse!!.cacheControl.maxAgeSeconds == -1 && expires == null

    init {
      if (cacheResponse != null) {
        this.sentRequestMillis = cacheResponse.sentRequestAtMillis