@Override
    public void shutdown() {
        super.shutdown();
        Monitors.unregisterObject(name, this);
    }
A connection pool that provides Servo counters to monitor the efficiency. 
Three counters are provided: counter for getting free entries (or reusing entries),
counter for creating new entries, and counter for every connection request.

@author awang
ribbon-httpclient/src/main/java/com/netflix/http4/NamedConnectionPool.java