* address for all hosts, regardless of the actual number of IP addresses reported by DNS.
   */
  fun newClient(): OkHttpClient {
    var client = testClient
    if (client == null) {
      client =
        initialClientBuilder()
          .dns(SINGLE_INET_ADDRESS_DNS) // Prevent unexpected fallback addresses.
          .eventListenerFactory { ClientRuleEventListener(logger = ::addEvent) }
          .build()