private val FRAME_NAMES =
    arrayOf(
      "DATA",
      "HEADERS",
      "PRIORITY",
      "RST_STREAM",
      "SETTINGS",
      "PUSH_PROMISE",
      "PING",
      "GOAWAY",
      "WINDOW_UPDATE",
      "CONTINUATION",
    )

  /**
   * Lookup table for valid flags for DATA, HEADERS, CONTINUATION. Invalid combinations are
   * represented in binary.
   */

  /** The total number of bytes produced by the application. */
  var writeBytesTotal = 0L
    internal set

  /** The total number of bytes permitted to be produced by incoming `WINDOW_UPDATE` frame. */
  var writeBytesMaximum: Long = connection.peerSettings.initialWindowSize.toLong()
    internal set

  /** Received headers yet to be [taken][takeHeaders]. */
  private val headersQueue = ArrayDeque<Headers>()

  /** The total number of bytes produced by the application. */
  var writeBytesTotal = 0L
    private set

  /** The total number of bytes permitted to be produced according to `WINDOW_UPDATE` frames. */
  var writeBytesMaximum: Long = peerSettings.initialWindowSize.toLong()
    private set

  internal val socket: BufferedSocket = builder.socket
  val writer = Http2Writer(socket.sink, client)