@Override
        public void run() {
            pool.flushTargets(false);
            jrtTask.schedule(1.0);
        }
Implements a helper class to invoke {@link RPCTargetPool#flushTargets(boolean)} once every second.
This is to untangle the target pool from the scheduler.
messagebus/src/main/java/com/yahoo/messagebus/network/rpc/RPCNetwork.java