}

  /**
   * Returns a human-readable representation of a `WINDOW_UPDATE` frame. This frame includes the
   * window size increment instead of flags.
   */
  fun frameLogWindowUpdate(
    inbound: Boolean,
    streamId: Int,
    length: Int,
    windowSizeIncrement: Long,
  ): String {
    val formattedType = formattedType(TYPE_WINDOW_UPDATE)
    val direction = if (inbound) "<<" else ">>"
    return format(

  @Test
  fun windowUpdateFrames() {
    assertThat(frameLogWindowUpdate(false, 0, 4, Int.MAX_VALUE.toLong()))
      .isEqualTo(">> 0x00000000     4 WINDOW_UPDATE 2147483647")
    assertThat(frameLogWindowUpdate(true, 101, 4, 1))
      .isEqualTo("<< 0x00000065     4 WINDOW_UPDATE 1")
  }

  @Test
  fun flagOverlapOn0x1() {
    assertThat(frameLog(true, 0, 0, TYPE_SETTINGS, 0x1))

[2020-01-01 00:00:00] >> 0x00000000     6 SETTINGS
[2020-01-01 00:00:00] >> 0x00000000     4 WINDOW_UPDATE
[2020-01-01 00:00:00] >> 0x00000003    47 HEADERS       END_STREAM|END_HEADERS
[2020-01-01 00:00:00] << 0x00000000     6 SETTINGS
[2020-01-01 00:00:00] << 0x00000000     0 SETTINGS      ACK
[2020-01-01 00:00:00] << 0x00000000     4 WINDOW_UPDATE
[2020-01-01 00:00:00] >> 0x00000000     0 SETTINGS      ACK

class WindowCounter(
  val streamId: Int,
) {
  /** The total number of bytes consumed. */
  var total: Long = 0L
    private set

  /** The total number of bytes acknowledged by outgoing `WINDOW_UPDATE` frames. */
  var acknowledged: Long = 0L
    private set

  val unacknowledged: Long
    @Synchronized get() = total - acknowledged

  @Synchronized
  fun update(
    total: Long = 0,

  ) {
    val increment: Long
    try {
      if (length != 4) throw IOException("TYPE_WINDOW_UPDATE length !=4: $length")
      increment = source.readInt() and 0x7fffffffL
      if (increment == 0L) throw IOException("windowSizeIncrement was 0")
    } catch (e: Exception) {
      logger.fine(frameLog(true, streamId, length, TYPE_WINDOW_UPDATE, flags))
      throw e
    }
    if (logger.isLoggable(FINE)) {
      logger.fine(

        length = 4,
        type = TYPE_WINDOW_UPDATE,
        flags = FLAG_NONE,
      )
      sink.writeInt(windowSizeIncrement.toInt())
      sink.flush()
    }
  }

  @Throws(IOException::class)
  fun frameHeader(
    streamId: Int,
    length: Int,
    type: Int,
    flags: Int,
  ) {
    if (type != TYPE_WINDOW_UPDATE && logger.isLoggable(FINE)) {

  /** 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>()

      this.data = debugData.toByteArray()
    }

    override fun windowUpdate(
      streamId: Int,
      windowSizeIncrement: Long,
    ) {
      check(type == -1)
      this.type = Http2.TYPE_WINDOW_UPDATE
      this.streamId = streamId
      this.windowSizeIncrement = windowSizeIncrement
    }

    override fun priority(
      streamId: Int,
      streamDependency: Int,
      weight: Int,

  /** 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: Socket = builder.socket
  val writer = Http2Writer(builder.sink, client)

    }
  }

  @Test fun windowUpdateRoundTrip() {
    val expectedWindowSizeIncrement: Long = 0x7fffffff
    writeMedium(frame, 4) // length
    frame.writeByte(Http2.TYPE_WINDOW_UPDATE)
    frame.writeByte(FLAG_NONE)
    frame.writeInt(expectedStreamId)
    frame.writeInt(expectedWindowSizeIncrement.toInt())

    // Check writer sends the same bytes.