Make use of Completer.isComplete in pub and pkg/scheduled_test.

utils/pub/io.dart

 // Copyright (c) 2012, 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.
 
 /// Helper functionality to make working with IO easier.
 library io;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
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 /// Wraps [input] to provide a timeout. If [input] completes before
 /// [milliseconds] have passed, then the return value completes in the same way.
 /// However, if [milliseconds] pass before [input] has completed, it completes
 /// with a [TimeoutException] with [description] (which should be a fragment
 /// describing the action that timed out).
 ///
 /// Note that timing out will not cancel the asynchronous operation behind
 /// [input].
 Future timeout(Future input, int milliseconds, String description) {
-  bool completed = false;
   var completer = new Completer();
   var timer = new Timer(new Duration(milliseconds: milliseconds), () {
-    completed = true;
     completer.completeError(new TimeoutException(
         'Timed out while $description.'));
   });
   input.then((value) {
-    if (completed) return;
+    if (completer.isCompleted) return;
     timer.cancel();
     completer.complete(value);
   }).catchError((e) {
-    if (completed) return;
+    if (completer.isCompleted) return;
     timer.cancel();
     completer.completeError(e.error, e.stackTrace);
   });
   return completer.future;
 }
 
 /// Creates a temporary directory and passes its path to [fn]. Once the [Future]
 /// returned by [fn] completes, the temporary directory and all its contents
 /// will be deleted.
 ///
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   const PubProcessResult(this.stdout, this.stderr, this.exitCode);
 
   bool get success => exitCode == 0;
 }
 
 /// Gets a [Uri] for [uri], which can either already be one, or be a [String].
 Uri _getUri(uri) {
   if (uri is Uri) return uri;
   return Uri.parse(uri);
 }