addOfflineNode(id, address, port) {
		const node = new Node(id);
		node.local = false;
		node.hostname = address;
		node.ipList = [address];
		node.port = port;
		node.available = false;
		node.seq = 0;
		node.offlineSince = Math.round(process.uptime());

		this.nodes.add(node.id, node);

		return node;
	}
Register a node as offline because we don't know all information about it

@param {String} id - NodeID
@param {String} address
@param {Number} port