Output of `go run cmd/demo-list/demo.go`:

```
Tracking Progress of 13 trackers ...

Calculating Total   #  1 ... done! [250 in 101ms]
Calculating Total   #  2 ... done! [2.00K in 101ms]
Downloading File    #  3 ... done! [6.75KB in 101ms]
Transferring Amount #  4 ... done! [$16.00K in 200ms]
Transferring Amount #  5 ... done! [£31.25K in 201ms]
Downloading File    #  6 ... done! [54.00KB in 300ms]
Calculating Total   #  7 ... done! [85.75K in 400ms]
Transferring Amount #  8 ... done! [$128.00K in 500ms]
Downloading File    #  9 ... done! [182.25KB in 700ms]
Transferring Amount # 10 ... done! [£250.00K in 801ms]
Calculating Total   # 11 ... done! [332.75K in 1s]
Transferring Amount # 12 ... done! [$432.00K in 1.2s]
Calculating Total   # 13 ... done! [549.25K in 1.301s]

All done!
```

Real-time playback of the demo @ asciinema.org:
[![asciicast](https://asciinema.org/a/KcPw8aoBSsYCBOj60wluhu5z3.png)](https://asciinema.org/a/KcPw8aoBSsYCBOj60wluhu5z3)
