public void addNode(T pNode, int vNodeCount) {
        if (vNodeCount < 0) throw new IllegalArgumentException("illegal virtual node counts :" + vNodeCount);
        int existingReplicas = getExistingReplicas(pNode);
        for (int i = 0; i < vNodeCount; i++) {
            VirtualNode<T> vNode = new VirtualNode<>(pNode, i + existingReplicas);
            ring.put(hashFunction.hash(vNode.getKey()), vNode);
        }
    }
add physic node to the hash ring with some virtual nodes
@param pNode physical node needs added to hash ring
@param vNodeCount the number of virtual node of the physical node. Value should be greater than or equals to 0
core/src/main/java/thirdparty/com/github/jaskey/consistenthash/ConsistentHashRouter.java