/**
   * Invoked after proxy selection.
   *
   * Note that the list of proxies is never null, but it may be a list containing
   * only [Proxy.NO_PROXY]. This comes up in several situations:
   *
   * * If neither a proxy nor proxy selector is configured.
   * * If the proxy is configured explicitly as [Proxy.NO_PROXY].
   * * If the proxy selector returns only [Proxy.NO_PROXY].
   * * If the proxy selector returns an empty list or null.
   *