anchor.diff:      // Shutdown HTTP server and subscription.
       Uri oldServerAddress = serverAddress;
       return cleanup(forced).then((_) {
  -      print('Observatory no longer listening on $oldServerAddress');
  +      serverPrint('Observatory no longer listening on $oldServerAddress');
         _server = null;
         _notifyServerState("");
         onServerAddressChange(null);
         return this;
       }).catchError((e, st) {
         _server = null;
  -      print('Could not shutdown Observatory HTTP server:\n$e\n$st\n');
  +      serverPrint('Could not shutdown Observatory HTTP server:\n$e\n$st\n');
         _notifyServerState("");
         onServerAddressChange(null);
         return this;
  
positive.code:       var message = new Message.fromUri(client, request.uri);
        client.onMessage(null, message);
      } catch (e) {
        print('Unexpected error processing HTTP request uri: '
              '${request.uri}\n$e\n');
        rethrow;
      }
    }
  
negative.code:       }
        _server = await HttpServer.bind(address, _port);
        _server.listen(_requestHandler, cancelOnError: true);
        serverPrint('Observatory listening on $serverAddress');
        // Server is up and running.
        _notifyServerState(serverAddress.toString());
        onServerAddressChange('$serverAddress');
        return this;
      } catch (e, st) {
        serverPrint('Could not start Observatory HTTP server:\n$e\n$st\n');
        _notifyServerState("");
        onServerAddressChange(null);
        return this;
  