throw ee.cause?.cause ?: ee.cause!!
    }
  }

  data class Response(
    val code: Int,
    val negotiatedProtocol: String,
    val content: String,
  )

  private fun execute(
    engine: HttpEngine,
    executor: ExecutorService,
    url: String,
  ): CompletableFuture<Response> {
    val completableFuture = CompletableFuture<Response>()
    val buffer = Buffer()

    val req =