client =
      client
        .newBuilder()
        .callTimeout(250, TimeUnit.MILLISECONDS)
        .build()
    server.enqueue(
      MockResponse
        .Builder()
        .bodyDelay(500, TimeUnit.MILLISECONDS)
        .setHeader("content-type", "text/event-stream")
        .body("data: hey\n\n")
        .build(),
    )
    val source = newEventSource()