class Redis::Cluster

def update_cluster_info!(node_key = nil) 

def update_cluster_info!(node_key = nil)
  unless node_key.nil?
    host, port = NodeKey.split(node_key)
    @option.add_node(host, port)
  end
  @node.map(&:disconnect)
  @node, @slot = fetch_cluster_info!(@option)
end