fun sendFrame(): Http2Writer {
    outFrames.add(OutFrame(frameCount++, bytesOut.size, false))
    return writer
  }

  /**
   * Shortens the last frame from its original length to `length`. This will cause the peer to
   * close the socket as soon as this frame has been written; otherwise the peer stays open until
   * explicitly closed.
   */
  fun truncateLastFrame(length: Int): Http2Writer {

      assertEquals(200, response.code)
      assertEquals("h3", response.negotiatedProtocol)
      assertTrue(response.content.contains("Disallow"))
    } catch (ee: ExecutionException) {
      throw ee.cause?.cause ?: ee.cause!!
    }
  }

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

  private fun execute(
    engine: HttpEngine,