public void primeConnections(List<Server> servers) {
        if (servers == null || servers.size() == 0) {
            logger.debug("No server to prime");
            return;
        }
        for (Server server: servers) {
            server.setReadyToServe(false);
        }
        int totalCount = (int) (servers.size() * primeRatio); 
        final CountDownLatch latch = new CountDownLatch(totalCount);
        final AtomicInteger successCount = new AtomicInteger(0);
        final AtomicInteger failureCount= new AtomicInteger(0);
        primeConnectionsAsync(servers, new PrimeConnectionListener()  {            
            @Override
            public void primeCompleted(Server s, Throwable lastException) {
                if (lastException == null) {
                    successCount.incrementAndGet();
                    s.setReadyToServe(true);
                } else {
                    failureCount.incrementAndGet();
                }
                latch.countDown();
            }
        }); 
                
        Stopwatch stopWatch = initialPrimeTimer.start();
        try {
            latch.await(maxTotalTimeToPrimeConnections, TimeUnit.MILLISECONDS);
        } catch (InterruptedException e) {
            logger.error("Priming connection interrupted", e);
        } finally {
            stopWatch.stop();
        }

        stats = new PrimeConnectionEndStats(totalCount, successCount.get(), failureCount.get(), stopWatch.getDuration(TimeUnit.MILLISECONDS));

        printStats(stats);
    }
Prime connections, blocking until configured percentage (default is 100%) of target servers are primed 
or max time is reached.

@see CommonClientConfigKey#MinPrimeConnectionsRatio
@see CommonClientConfigKey#MaxTotalTimeToPrimeConnections
ribbon-loadbalancer/src/main/java/com/netflix/client/PrimeConnections.java