@Override
    protected BasicPoolEntry getEntryBlocking(HttpRoute route, Object state,
            long timeout, TimeUnit tunit, WaitingThreadAborter aborter)
            throws ConnectionPoolTimeoutException, InterruptedException {
        Stopwatch stopWatch = requestTimer.start();
        try {
            return super.getEntryBlocking(route, state, timeout, tunit, aborter);
        } finally {
            stopWatch.stop();
        }
    }
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