val cacheResponse: Response?,
) {
  class Factory(
    private val nowMillis: Long,
    internal val request: Request,
    private val cacheResponse: Response?,
  ) {
    /** The server's time when the cached response was served, if known. */
    private var servedDate: Date? = null
    private var servedDateString: String? = null

    /** The last modified date of the cached response, if known. */