dart - 监听HttpClientResponse总是抛出

Question

import 'dart:io';
import 'dart:async';

void main() {
  HttpClient client = new HttpClient();
  client.getUrl(Uri.parse('http://api.dartlang.org/docs/releases/latest/dart_io/HttpClientResponse.html'))
    .then((HttpClientRequest request) => request.close())
    .then((HttpClientResponse response) {
      response.listen(print, onError: (e) {
        print('error: $e');
      }); 
    });
}

上面的代码不起作用，使用类似的方法像pipe和fold一样侦听也抛出异常=> Breaking on exception: The null object does not have a method 'cancel'.
更新

这是连接到本地计算机时的代码示例。

import 'dart:io';
import 'dart:async';

void main() {
  HttpServer.bind('127.0.0.1', 8080)
    .then((HttpServer server) {
      server.listen((HttpRequest request) {
        File f = new File('upload.html');
        f.openRead().pipe(request.response);
      });

      HttpClient client = new HttpClient();
      client.getUrl(Uri.parse('http://127.0.0.1:8080'))
        .then((HttpClientRequest request) => request.close())
          .then((HttpClientResponse response) {
            response.listen(print, onError: (e) {
              print('error: $e');
            });
          });
    });
}

它先打印出字节，然后抛出异常Breaking on exception: The null object does not have a method 'cancel'.
Dart编辑器0.7.2_r27268版本。 Dart SDK版本0.7.2.1_r27268。在Windows 64位计算机上。

Answer 1

您的示例适用于我的机器。

请指定您的Dart版本和其他有助于调试问题的系统属性。