该项目是 systemd 的 Go 语言绑定版本，提供如下几个包：
activation - for writing and using socket activation from Go
dbus - for starting/stopping/inspecting running services and units
journal - for writing to systemd’s logging service, journald
sdjournal - for reading from journald by wrapping its C API
machine1 - for registering machines/containers with systemd
unit - for (de)serialization and comparison of unit files
