|  | // 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. | 
|  |  | 
|  | part of dart.developer; | 
|  |  | 
|  | /// A UserTag can be used to group samples in the | 
|  | /// [DevTools CPU profiler](https://docs.flutter.dev/tools/devtools/cpu-profiler). | 
|  | abstract final class UserTag { | 
|  | /// The maximum number of UserTag instances that can be created by a program. | 
|  | static const maxUserTags = 64; | 
|  |  | 
|  | external factory UserTag(String label); | 
|  |  | 
|  | /// Label of this [UserTag]. | 
|  | String get label; | 
|  |  | 
|  | /// Make this [UserTag] the current tag for the isolate. Returns the current | 
|  | /// tag before setting. | 
|  | UserTag makeCurrent(); | 
|  |  | 
|  | /// The default [UserTag] with label 'Default'. | 
|  | external static UserTag get defaultTag; | 
|  | } | 
|  |  | 
|  | /// Returns the current [UserTag] for the isolate. | 
|  | external UserTag getCurrentTag(); |