const val TYPE_PRIORITY = 0x2
  const val TYPE_RST_STREAM = 0x3
  const val TYPE_SETTINGS = 0x4
  const val TYPE_PUSH_PROMISE = 0x5
  const val TYPE_PING = 0x6
  const val TYPE_GOAWAY = 0x7
  const val TYPE_WINDOW_UPDATE = 0x8
  const val TYPE_CONTINUATION = 0x9

  const val FLAG_NONE = 0x0
  const val FLAG_ACK = 0x1 // Used for settings and ping.
  const val FLAG_END_STREAM = 0x1 // Used for headers and data.

  ) {
    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)) {

      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,

    }
  }

  @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.

    for (i in 0..2) {
      val windowUpdateStreamIds: MutableList<Int?> = ArrayList(2)
      for (j in 0..1) {
        val windowUpdate = peer.takeFrame()
        assertThat(windowUpdate.type).isEqualTo(Http2.TYPE_WINDOW_UPDATE)
        windowUpdateStreamIds.add(windowUpdate.streamId)
        assertThat(windowUpdate.windowSizeIncrement).isEqualTo(windowUpdateThreshold.toLong())
      }
      // connection