Logs a message. All messages get prefixed with '[SERVER]'
           and the arguments act like `format`.

def log_message(self, format, *args):
        """Logs a message. All messages get prefixed with '[SERVER]'
           and the arguments act like `format`.
        """
        clock_start = getattr(thread_local, 'clock_start', None)
        thread_local.clock_start = None
        timing = self.log_elapsed_time_string(
            get_time() - clock_start) if clock_start is not None else ''
        msg("%s[%s] %s" % (
            timing + ' ' if len(timing) else '', self.log_date_time_string(),
            format % args))