private val hpackReader: Hpack.Reader =
    Hpack.Reader(
      source = continuation,
      headerTableSizeSetting = 4096,
    )

  @Throws(IOException::class)
  fun readConnectionPreface(handler: Handler) {
    if (client) {
      // The client reads the initial SETTINGS frame.
      if (!nextFrame(true, handler)) {
        throw IOException("Required SETTINGS preface not received")
      }

    override fun invoke() {
      var connectionErrorCode = ErrorCode.INTERNAL_ERROR
      var streamErrorCode = ErrorCode.INTERNAL_ERROR
      var errorException: IOException? = null
      try {
        reader.readConnectionPreface(this)
        while (reader.nextFrame(false, this)) {
        }
        connectionErrorCode = ErrorCode.NO_ERROR
        streamErrorCode = ErrorCode.CANCEL
      } catch (e: IOException) {