Troubleshoot dbus connections

Obviously, you can replace "info" by "debug" to get more logs

1 Fetch the list of units on the user session bus

RUST_LOG="info"  sysd-manager  --user --test unit_list

dbus-send equivalent

dbus-send --session --print-reply --dest=org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager.ListUnits

2 Fetch the list of units on the system bus

RUST_LOG="info" sysd-manager  --system --test unit_list

dbus-send equivalent

dbus-send --system --print-reply --dest=org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager.ListUnits

3 Fetch the list of unit files on the user session bus

RUST_LOG="info" sysd-manager --user --test unit_file_list 

dbus-send equivalent

dbus-send --session --print-reply --dest=org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager.ListUnitFiles

4 Fetch the list of unit files on the system bus

RUST_LOG="info" sysd-manager --system --test unit_file_list 

dbus-send equivalent

dbus-send --system --print-reply --dest=org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager.ListUnitFiles