the date in the local time zone: 2009/01/23.

full file name and line number: /a/b/c/d.go:23.

microsecond resolution: 01:23:23.123123.

final file name element and line number: d.go:23.

initial values for the standard logger.

the time in the local time zone: 01:23:23.

if Ldate or Ltime is set, use UTC rather than the local time zone.