Arch Linux

Description:

I have a local script to run pacman (and a few other update processes) in tmux panels. It was working fine until curl 7.84 was released. Since then, the pacman process systematically fails with the error:
```
error: curl returned error 12 from transfer
error: failed to synchronize all databases (unexpected error)
```

This is my (simplified) update script:

```
tmux new-session -d -s up
tmux split-window -v

tmux select-pane -t 0

tmux select-pane -t 0
tmux send-keys 'sudo pacman -Syy --noconfirm' C-m
tmux attach -t up
```

(Note that I have `sudo` set to allow pacman without password, which means pacman starts immediately in the script, without a potential delay from typing the password.)

With curl 7.84.0-1 installed, this systematically fails.
A few actions can prevent this failure:
- After downgrading to curl 7.83.1-1, I cannot reproduce the issue. After upgrading back to 7.84.0-1, the issue is back.
- If I add a delay longer than ~0.3s before the update, it also removes the issue. If the delay is too short (~0.1), the issue is back. With a delay of ~0.2, the issue is random.
- If I manually run the command, it works fine (most likely because it takes me more than 0.2s to run the command manually)
- If I update the script to not split the window, the issue also disappears.

This makes me think that the issue is caused by some race condition between the pacman process using libcurl and maybe the shell (zsh) initializing in the other panel. This zsh process is most likely doing all sort of stuff when initializing, but I would _hope_ that being separate processes, they would not interact like that.

This happens with an empty `~/.zshrc`. I had `grml-zsh-config` installed, but this still happens after I uninstall it.

Additional info:
* package version(s): pacman 6.0.1-5, tmux 3.3_a-2,
* The shell configured is zsh.
* link to upstream bug report, if any