lag issue when showing files tab ( Files [3] ) with 0.22.1

[MartinVincent]

Describe the bug
When upgrading from 0.22.0 to 0.22.1, I noticed a lag when showing files tab (Files [3]), which was absent in 0.22.0.

To Reproduce

1. Setup env:

~/Code ❯ git clone https://github.com/extrawurst/gitui.git

Cloning into 'gitui'...
cd gitui
 ~/Code ❯ cd gitui/
 [master:ca19d42  ] ~/Code/gitui ❯ gitui_0.22.1 --version
gitui 0.22.1

2. Run gitui
3. Naviagte to tab 3: Files[3]
   • wait ~N seconds for files to show

Expected behavior
Expected the same behaviour as what was present in past versions: quasi instantaneous display of the files.

Screenshots
asciinema film/capture showing the difference between 0.22.0 and 0.22.1:

Context (please complete the following information):

• Ubuntu 20.04.02 LTS
• GitUI Version 0.22.1
• cargo 1.60.0 (d1fd9fe 2022-03-01)

[extrawurst]

Please compare again via switching to the tab after the app start. In your comparison the app start mode hide the lag in 0.22.0.

because this is exactly what I addressed in 8e8c5fa

[MartinVincent]

Hum, problem persists AFAICT:

[extrawurst]

fixed. I forgot the debug code in there :(