@Test
  fun upgrade() {
    val socketHandler =
      MockSocketHandler()
        .apply {
          receiveRequest("client says hello\n")
          sendResponse("server says hello\n")
          receiveRequest("client says goodbye\n")
          sendResponse("server says goodbye\n")
          exhaustResponse()
          exhaustRequest()
        }
    server.enqueue(socketHandler.upgradeResponse())

    client

        try {
          stream.source.exhausted()
          throw AssertionError("expected IOException")
        } catch (expected: IOException) {
        }
      }
    }

  @JvmOverloads
  fun sendResponse(
    s: String,
    responseSent: CountDownLatch = CountDownLatch(1),
  ) = apply {
    actions += { stream ->
      stream.sink.writeUtf8(s)
      stream.sink.flush()
      responseSent.countDown()
    }