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

dart/tests/standalone/io/http_client_stays_alive_test.dart

+import 'dart:io';
+
+const SECONDS = 10;
+
+void runServerProcess() {
+  HttpServer.bind('127.0.0.1', 0).then((server) {
+    var url = 'http://127.0.0.1:${server.port}/';
+
+    server.idleTimeout = const Duration(hours: 1);
+
+    var subscription = server.listen((HttpRequest request) {
+      return request.response..write('hello world')..close();
+    });
+
+    var sw = new Stopwatch()..start();
+    Process.run(Platform.executable, ['${Platform.script}', url]).then((res) {
+      subscription.cancel();
+      if (res.exitCode != 0) {
+        throw "Child exited with ${res.exitCode} instead of 0";
+      }
+      var seconds = sw.elapsed.inSeconds;
+      if ((SECONDS - seconds).abs() > 2) {

[Søren Gjesse, 2014/08/26 06:56:05]

Of cause this has flake potential... but maybe 2 sec slack is sufficient?

[kustermann, 2014/08/26 09:37:27]

For the DartVM 2 seconds is a huge time.

In fact ]SECONDS-2.99,SECONDS+2.99[ should count as good.

+        throw "Child did exit within $seconds seconds, but expected it to take "
+              "roughly $SECONDS seconds.";
+      }
+    });
+  });
+}
+
+void runClientProcess(String url) {
+  var uri = Uri.parse(url);
+
+  // NOTE: We make an HTTP client request and then *forget to close* the HTTP
+  // client instance. The idle timer should fire after SECONDS.
+  var client = new HttpClient();
+  client.idleTimeout = const Duration(seconds: SECONDS);
+
+  client.getUrl(uri)
+      .then((req) =>req.close())
+      .then((response) => response.drain())
+      .then((_) => print('drained client request'));
+}
+
+void main(List<String> args) {
+  if (args.length == 1) {
+    runClientProcess(args.first);
+  } else {
+    runServerProcess();
+  }
+}