Make new StreamController().isPaused be true until the first listener arrives.

runtime/bin/socket_patch.dart

Index: runtime/bin/socket_patch.dart
diff --git a/runtime/bin/socket_patch.dart b/runtime/bin/socket_patch.dart
index 81c89754185be05f6150463181549a4dc8ffa79e..d86a17c1d8de72491c92c29d068310286db63a87 100644
--- a/runtime/bin/socket_patch.dart
+++ b/runtime/bin/socket_patch.dart
@@ -700,7 +700,7 @@ class _RawSocket extends Stream<RawSocketEvent>
   void set readEventsEnabled(bool value) {
     if (value != _readEventsEnabled) {
       _readEventsEnabled = value;
-      if (_controller.hasListener && !_controller.isPaused) _resume();
+      if (!_controller.isPaused) _resume();
     }
   }
 
@@ -708,7 +708,7 @@ class _RawSocket extends Stream<RawSocketEvent>
   void set writeEventsEnabled(bool value) {
     if (value != _writeEventsEnabled) {
       _writeEventsEnabled = value;
-      if (_controller.hasListener && !_controller.isPaused) _resume();
+      if (!_controller.isPaused) _resume();
     }
   }