Function syslog::init

pub fn init(
    facility: Facility, 
    log_level: LevelFilter, 
    application_name: Option<&str>
) -> Result<()>

Initializes logging subsystem for log crate

This tries to connect to syslog by following ways:

1. Unix sockets /dev/log and /var/run/syslog (in this order)
2. Tcp connection to 127.0.0.1:601
3. Udp connection to 127.0.0.1:514

Note the last option usually (almost) never fails in this method. So this method doesn't return error even if there is no syslog.

If application_name is None name is derived from executable name