模块配置使用：

================= example ==================
> curl http://yourip/metric_status

{"1xx":0,"2xx":21715,"3xx":48,"4xx":94,"5xx":2,"total":21859,"avg_time":0.036,"min_time":0.001,"max_time":10.484}


================= nginx.conf ===============

metric_zone  size=10M min_time=10ms max_time=10s;
metric  on;

server {
    listen  80;

    location / {
        root  html;
    }

    location /metric_status {
	metric_status  on;
        metric  off;
    }

    location /metric_reset {
	metric_reset  on;
        metric  off;
    }
}