func (l *slog) Critical(args ...interface{}) {
	lvl := l.Level()
	if lvl <= LevelCritical {
		l.b.print("CRT", l.tag, args...)
	}
}
func (l *slog) Critical(args ...interface{}) {
	lvl := l.Level()
	if lvl <= LevelCritical {
		l.b.print("CRT", l.tag, args...)
	}
}
// Critical formats message using the default formats for its operands, prepends
// the prefix as necessary, and writes to log with LevelCritical.
//
// This is part of the Logger interface implementation.