How best to close WebSocketServer

[mhkeller]

Following the example of the Node backend here:

const { WebSocketServer, table } = require("@finos/perspective");
const fs = require("fs");

// Start a WS/HTTP host on port 8080.  The `assets` property allows
// the `WebSocketServer()` to also serves the file structure rooted in this
// module's directory.
const host = new WebSocketServer({ assets: [__dirname], port: 8080 });

// Read an arrow file from the file system and host it as a named table.
const arr = fs.readFileSync(__dirname + "/superstore.lz4.arrow");
await table(arr, { name: "table_one" });

What's the proper way to close this server? Looking at the source code, I see it has _server and _wss properties, which I assume both have .close() methods. There may also be a top level .close() method on the returned host variable but I couldn't find in the docs where the various methods might be described. If anyone has any guidance for how to close out a server, that would be great.