code: function calcFsSpeed(rx, wx) {
    let result = {
      rx: 0,
      wx: 0,
      tx: 0,
      rx_sec: -1,
      wx_sec: -1,
      tx_sec: -1,
      ms: 0
    };
  
    if (_fs_speed && _fs_speed.ms) {
      result.rx = rx;
      result.wx = wx;
      result.tx = result.rx + result.wx;
      result.ms = Date.now() - _fs_speed.ms;
      result.rx_sec = (result.rx - _fs_speed.bytes_read) / (result.ms / 1000);
      result.wx_sec = (result.wx - _fs_speed.bytes_write) / (result.ms / 1000);
      result.tx_sec = result.rx_sec + result.wx_sec;
      _fs_speed.rx_sec = result.rx_sec;
      _fs_speed.wx_sec = result.wx_sec;
      _fs_speed.tx_sec = result.tx_sec;
      _fs_speed.bytes_read = result.rx;
      _fs_speed.bytes_write = result.wx;
      _fs_speed.bytes_overall = result.rx + result.wx;
      _fs_speed.ms = Date.now();
      _fs_speed.last_ms = result.ms;
    } else {
      result.rx = rx;
      result.wx = wx;
      result.tx = result.rx + result.wx;
      _fs_speed.rx_sec = -1;
      _fs_speed.wx_sec = -1;
      _fs_speed.tx_sec = -1;
      _fs_speed.bytes_read = result.rx;
      _fs_speed.bytes_write = result.wx;
      _fs_speed.bytes_overall = result.rx + result.wx;
      _fs_speed.ms = Date.now();
      _fs_speed.last_ms = 0;
    }
    return result;
  }
docs: -------------------------- FS - speed