sink.writeUtf8(data)
    sink.close()
    return result
  }

  private fun cancelLater(
    call: Call,
    delay: Long,
  ): Thread {
    val thread =
      object : Thread("canceler") {
        override fun run() {
          try {
            sleep(delay)
          } catch (e: InterruptedException) {
            throw AssertionError()
          }
          call.cancel()