private fun readWindowUpdate(
    handler: Handler,
    length: Int,
    flags: Int,
    streamId: Int,
  ) {
    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) {