@Override
        public String toString() {
            return "PrimeConnectionEndStats [total=" + total + ", success="
                + success + ", failure=" + failure + ", totalTime="
                + totalTime + "]";
        }
Prime the connections for a given Client (For those Client that
have a LoadBalancer that knows the set of Servers it will connect to) This is
mainly done to address those deployment environments (Read EC2) which benefit
from a firewall connection/path warmup prior to actual use for live requests.
<p>
This class is not protocol specific. Actual priming operation is delegated to 
instance of {@link IPrimeConnection}, which is instantiated using reflection
according to property {@link CommonClientConfigKey#PrimeConnectionsClassName}.

@author stonse
@author awang
@author aspyker
ribbon-loadbalancer/src/main/java/com/netflix/client/PrimeConnections.java