为什么在我的dart渡槽服务器中忽略main.dart配置

渡槽服务器的main.dart文件是

import 'package:dart_server/dart_server.dart';

Future main() async {
  final app = Application<DartServerChannel>()
      ..options.configurationFilePath = "config.yaml"
      ..options.port = 3000;                          // changed from 8888

  final count = Platform.numberOfProcessors ~/ 2;
  await app.start(numberOfInstances: 1);              // changed from count > 0 ? count : 1 

  print("Application started on port: ${app.options.port}.");
  print("Use Ctrl-C (SIGINT) to stop running the application.");
}

我更改了端口号和实例数,但是当我用

aqueduct serve

-- Aqueduct CLI Version: 3.1.0+1
-- Aqueduct project version: 3.1.0+1
-- Preparing...
-- Starting application 'dart_server/dart_server'
    Channel: DartServerChannel
    Config: /Users/jonathan/Documents/Programming/Tutorials/Flutter/backend/backend_app/dart_server/config.yaml
    Port: 8888
[INFO] aqueduct: Server aqueduct/1 started.  
[INFO] aqueduct: Server aqueduct/2 started. 

只有当我像这样显式地启动服务器时

aqueduct serve --port 3000 --isolates 1

我有端口3000和一个实例吗:

-- Aqueduct CLI Version: 3.1.0+1
-- Aqueduct project version: 3.1.0+1
-- Preparing...
-- Starting application 'dart_server/dart_server'
    Channel: DartServerChannel
    Config: /Users/jonathan/Documents/Programming/Tutorials/Flutter/backend/backend_app/dart_server/config.yaml
    Port: 3000
[INFO] aqueduct: Server aqueduct/1 started.