val socket = peer.openSocket()
    val connection =
      Http2Connection.Builder(true, TaskRunner.INSTANCE)
        .socket(socket)
        .pushObserver(IGNORE)
        .build()
    connection.start(sendConnectionPreface = false)
    socket.shutdownOutput()
    assertFailsWith<IOException> {
      connection.newStream(headerEntries("a", longString), false)
    }
    assertFailsWith<IOException> {

      taskFaker.sleep(100.µs)
      log += "red:finishing@${taskFaker.nanoTime}"
    }
    assertThat(taskFaker.executeCallCount).isEqualTo(1)

    // Enqueueing the blue task doesn't start a thread because the red one is still starting.
    blueQueue.execute("blue task") {
      log += "blue:starting@${taskFaker.nanoTime}"
      taskFaker.sleep(100.µs)
      log += "blue:finishing@${taskFaker.nanoTime}"