@ArgumentsSource(ProtocolParamProvider::class)
  fun connectionReuse(protocol: Protocol) {
    setUp(protocol)
    server.enqueue(MockResponse(body = "ABCDEF"))
    server.enqueue(MockResponse(body = "GHIJKL"))
    val call1 = client.newCall(Request(server.url("/r1")))
    val call2 = client.newCall(Request(server.url("/r1")))
    val response1 = call1.execute()
    val response2 = call2.execute()