// Internal state is guarded by `this`. No long-running or potentially blocking operations are
  // performed while the lock is held.

  /** The bytes consumed and acknowledged by the stream. */
  val readBytes: WindowCounter = WindowCounter(id)

  /** 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. */

   * never mutated once it has been assigned.
   */
  var peerSettings = DEFAULT_SETTINGS

  /** The bytes consumed and acknowledged by the application. */
  val readBytes: WindowCounter = WindowCounter(streamId = 0)

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