Bug: changing volume affects CPU usage

In my `.i3status.conf` file I have:

```
order += "volume master"
order += "cpu_usage"

volume master {
separator_block_width = 10
format = "♪:%volume"
format_muted = "♪:(%volume)"
device = "default"
mixer = "Master"
mixer_idx = 0
}

cpu_usage {
separator_block_width = 10
format = "CPU:%usage"
}
```

When I increase or decrease my volume, the CPU usage abnormally fluctuates +20-30% and then goes back to the previous state after a few seconds.

I suspect the issue is with the `volume` directive as removing it from the config file resolves the issue.

There is a similar issue reported here: https://www.reddit.com/r/i3wm/comments/jf7i1s/i3bar_cpu_usage_immediately_jumps_to_a_set_figure/