Fix idle connection pool issue in dart:io's HttpClient

dart/tests/standalone/io/http_client_timeout_test.dart

-// Copyright (c) 2013, 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.
-
-import 'dart:async';
-import 'dart:io';
-
-
-void testOneRequest(int connections) {
-  HttpServer.bind('127.0.0.1', 0).then((server) {
-    server.listen((request) => request.response.close());
-    var client = new HttpClient();
-    var futures = [];
-    for (int i = 0; i < connections; i++) {
-      futures.add(
-          client.get('127.0.0.1', server.port, '/')
-              .then((request) => request.close())
-              .then((response) => response.fold(null, (x, y) {})));
-    }
-    Future.wait(futures).then((_) {
-      new Timer.periodic(const Duration(milliseconds: 100), (timer) {
-        if (server.connectionsInfo().total == 0) {
-          timer.cancel();
-          server.close();
-        }
-      });
-    });
-  });
-}
-
-
-void testIdleTimeout(int timeout) {
-  HttpServer.bind('127.0.0.1', 0).then((server1) {
-    HttpServer.bind('127.0.0.1', 0).then((server2) {
-      server1.listen((request) => request.pipe(request.response));
-      server2.listen((request) => request.pipe(request.response));
-
-      var client = new HttpClient();
-      client.idleTimeout = new Duration(milliseconds: timeout);
-
-      // Create a 'slow' connection..
-      Future connect(int port) {
-        return client.post('127.0.0.1', port, '/')
-            .then((request) {
-              request.write("data");
-              new Timer(const Duration(milliseconds: 250), () {
-                request.close();
-              });
-              return request.done;
-            })
-            .then((response) {
-              return response.fold(null, (x, y) {});
-            });
-      }
-
-      // Create a single, slow request, to server1.
-      connect(server1.port);
-
-      // Create a repeating connection to server2.
-      run() {
-        connect(server2.port).then((_) {
-          if (server1.connectionsInfo().total == 0) {
-            server1.close();
-            server2.close();
-            return;
-          }
-          Timer.run(run);
-        });
-      }
-      run();
-    });
-  });
-}
-
-
-main() {
-  testOneRequest(1);
-  testOneRequest(5);
-  testOneRequest(20);
-  testIdleTimeout(0);
-  testIdleTimeout(100);
-  testIdleTimeout(500);
-  testIdleTimeout(1000);
-  testIdleTimeout(2000);
-}