Function syslog_identifier 

pub fn syslog_identifier() -> String

Determine the syslog identifier for this process.

This function obtains the syslog identifier from the file name of the current executable, per std::env::current_exe.

As such, it’s a comparatively expensive function to call; implementations of LogControl1 should avoid calling it for every invocation, but instead determine the identifier once upon construction and store it.

If it fails to determine the syslog identifier, i.e. when current_exe returns an error, this function falls back to the empty string.