code: synchronized void openConnection(final ModelController controller, final ActiveOperation.CompletedCallback<ModelNode> callback) throws Exception {
          boolean ok = false;
          final Connection connection = connectionManager.connect();
          try {
              channelHandler.executeRequest(new ServerRegisterRequest(), null, callback);
              // HC is the same version, so it will support sending the subject
              channelHandler.getAttachments().attach(TransactionalProtocolClient.SEND_IDENTITY, Boolean.TRUE);
              channelHandler.getAttachments().attach(TransactionalProtocolClient.SEND_IN_VM, Boolean.TRUE);
              channelHandler.addHandlerFactory(new TransactionalProtocolOperationHandler(controller, channelHandler, responseAttachmentSupport));
              ok = true;
          } finally {
              if(!ok) {
                  connection.close();
              }
          }
      }
docs: Connect to the HC and retrieve the current model updates.
  
  @param controller the server controller
  @param callback the operation completed callback
  
  @throws IOException for any error