anchor.diff:      if (_evictionTimer == null) {
         void _handleEviction(Timer timer) {
           Date now = new Date.now();
  +        List<String> emptyKeys = new List<String>();
           _openSockets.forEach(
               void _(String key, Queue<_SocketConnection> connections) {
                 // As returned connections are added at the head of the
  
positive.code:      _activeSockets.forEach((_SocketConnection socketConn) {
         socketConn._socket.close();
       });
       if (_evictionTimer != null) {
         _evictionTimer.cancel();
       }
       _shutdown = true;
    }
  
    String _connectionKey(String host, int port) {
  
negative.code:       new Timer(0, (ignored) => _connectionOpened(socketConn, connection));
  
        // Get rid of eviction timer if there are no more active connections.
        if (socketConnections.isEmpty()) _openSockets.remove(key);
        if (_openSockets.isEmpty()) _cancelEvictionTimer();
      }
  
      return connection;
  