.build()
    assertFailsWith<IOException> {
      client.newCall(Request.Builder().url(server.url("/0")).build()).execute()
    }.also { expected ->
      assertThat(expected.message).isEqualTo("Too many follow-up requests: 21")
    }
  }

  /**
   * We had a bug where we were passing a null route to the authenticator.
   * https://github.com/square/okhttp/issues/3809
   */
  @Test