code: function createServer(bs) {
      var proxy = bs.options.get("proxy");
      var server = bs.options.get("server");
  
      if (!proxy && !server) {
          return require("./snippet-server")(bs);
      }
  
      if (proxy) {
          return require("./proxy-server")(bs);
      }
  
      if (server) {
          return require("./static-server")(bs);
      }
  }
docs: Launch the server for serving the client JS plus static files
  @param {BrowserSync} bs
  @returns {{staticServer: (http.Server), proxyServer: (http.Server)}}