private fun evictToRecoverBytes(bytesToRecover: Int): Int {
        var bytesToRecover = bytesToRecover
        var entriesToEvict = 0
        if (bytesToRecover > 0) {
          // determine how many headers need to be evicted.
          var j = dynamicTable.size - 1
          while (j >= nextHeaderIndex && bytesToRecover > 0) {
            bytesToRecover -= dynamicTable[j]!!.hpackSize