Use native async/await support in pub.

sdk/lib/_internal/pub_generated/lib/src/barback/admin_server.dart

-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library pub.barback.admin_server;
-
-import 'dart:async';
-import 'dart:io';
-
-import 'package:http_parser/http_parser.dart';
-import 'package:shelf/shelf.dart' as shelf;
-import 'package:shelf_web_socket/shelf_web_socket.dart';
-
-import '../io.dart';
-import '../log.dart' as log;
-import 'asset_environment.dart';
-import 'base_server.dart';
-import 'web_socket_api.dart';
-
-/// The web admin interface to pub serve.
-// TODO(rnystrom): Currently this just provides access to the Web Socket API.
-// See #16954.
-class AdminServer extends BaseServer {
-  /// All currently open [WebSocket] connections.
-  final _webSockets = new Set<CompatibleWebSocket>();
-
-  shelf.Handler _handler;
-
-  /// Creates a new server and binds it to [port] of [host].
-  static Future<AdminServer> bind(AssetEnvironment environment, String host,
-      int port) {
-    return bindServer(host, port).then((server) {
-      log.fine('Bound admin server to $host:$port.');
-      return new AdminServer._(environment, server);
-    });
-  }
-
-  AdminServer._(AssetEnvironment environment, HttpServer server)
-      : super(environment, server) {
-    _handler = new shelf.Cascade().add(
-        webSocketHandler(_handleWebSocket)).add(_handleHttp).handler;
-  }
-
-  /// Closes the server and all Web Socket connections.
-  Future close() {
-    var futures = [super.close()];
-    futures.addAll(_webSockets.map((socket) => socket.close()));
-    return Future.wait(futures);
-  }
-
-  handleRequest(shelf.Request request) => _handler(request);
-
-  /// Handles an HTTP request.
-  _handleHttp(shelf.Request request) {
-    // TODO(rnystrom): Actually respond to requests once there is an admin
-    // interface. See #16954.
-    logRequest(request, "501 Not Implemented");
-    return new shelf.Response(
-        501,
-        body: "Currently this server only accepts Web Socket connections.");
-  }
-
-  /// Creates a web socket for [request] which should be an upgrade request.
-  void _handleWebSocket(CompatibleWebSocket socket) {
-    _webSockets.add(socket);
-    var api = new WebSocketApi(socket, environment);
-    api.listen().whenComplete(
-        () => _webSockets.remove(api)).catchError(addError);
-  }
-}