Hi,
we're using uim on immutable images built from Debian. Upon first
boot `/var` is empty, see e.g.

https://0pointer.net/blog/projects/stateless.html

Since uim keeps about registered modules in `/var` no input methods are
available. We're currently using a systemd unit to populate /var/lib/uim:


https://salsa.debian.org/BengalOS-team/pkgs/bengalos/-/merge_requests/12

but it would be nice if uim in Debian would handle that so it can work
for other immutable distros like ParticleOS too. The idea would be:

Have uim ship a unit like:

```
[Unit]
Description=Setup UIM modules
After=dbus.service
ConditionPathExists=!/var/lib/uim

[Service]
Type=oneshot
ExecStart=mkdir -p /var/lib/uim
ExecStart=uim-module-manager --unregister-all --path /var/lib/uim

[Install]
WantedBy=multi-user.target
```

Each uim module (e.g. uim-anthy) would then add an override
(/usr/lib/systemd/system/uim.conf.d/10-uim-anty.conf) file:

```
[Service]
ExecStart=uim-module-manager --register anthy-utf8 --path /var/lib/uim
```

That would ensure registartion on immutable systems on first boot. I can
send patches if that makes sense.

Cheers,
 -- Guido