code: func (f *FileLogger) pc(str string) {
  	if f.logConsole {
  		if log.Prefix() != f.prefix {
  			log.SetPrefix(f.prefix)
  		}
  		log.Println(str)
  	}
  }
docs: // print log in console, default log string wont be print in console
  // NOTICE: when console is on, the process will really slowly