text: import time
  from dash.exceptions import PreventUpdate
  from dash_extensions.enrich import DashProxy, dcc, html, Output, Input, BlockingCallbackTransform
  
  app = DashProxy(transforms=[BlockingCallbackTransform(timeout=10)])
  app.layout = html.Div([html.Div(id="output"), dcc.Interval(id="trigger")])   # default interval is 1s
  
  @app.callback(Output("output", "children"), Input("trigger", "n_intervals"), blocking=True)
  def update(n_intervals):
      if not n_intervals:
          raise PreventUpdate()
      time.sleep(2)  # emulate slow database
      return f"Hello! (n_intervals is {n_intervals})"
  
  if __name__ == '__main__':
      app.run_server()