Put delivering of parsed http-requests at the end of the message-queue.

sdk/lib/io/http_impl.dart

Index: sdk/lib/io/http_impl.dart
diff --git a/sdk/lib/io/http_impl.dart b/sdk/lib/io/http_impl.dart
index c7e1a5f4a714a0a8920e36fb1980fbff6b4a6262..e4f366db1bf47e61c5e423f52e90ff6f7a7a2c1d 100644
--- a/sdk/lib/io/http_impl.dart
+++ b/sdk/lib/io/http_impl.dart
@@ -2190,7 +2190,17 @@ class _HttpServer
     _sessionManager.sessionTimeout = timeout;
   }
 
-  void _handleRequest(HttpRequest request) => _controller.add(request);
+  void _handleRequest(_HttpRequest request) {
+    // Delay the request until the isolate's message-queue is handled.
+    // This greatly improves scheduling when a lot of requests are active.
+    Timer.run(() {
+      if (!closed) {
+        _controller.add(request);
+      } else {
+        request._httpConnection.destroy();
+      }
+    });
+  }
 
   void _handleError(error) {
     if (!closed) _controller.addError(error);