title: R shiny busy global indicator
body: <p>Is there a global busy indicator for R shiny/dashboard applications.
  I do not want to set an indicator to each chunk everytime like the example given below:
  <a href="https://mastering-shiny.org/action-feedback.html?q=progr#progress-bars" rel="nofollow noreferrer">https://mastering-shiny.org/action-feedback.html?q=progr#progress-bars</a></p>
  <p>But I am looking for something that I want to set <strong>once</strong> and it will simple indicate busy notifications <strong>whenever</strong> shiny server is making a somewhat long calculations (10/30 seconds).</p>
  <p>I think this should be a default behaviour of shiny but I could not see anywhere something like this.</p>
  <p>I saw this library but did not work:
  <a href="https://cran.r-project.org/web/packages/shinybusy/vignettes/shinybusy-usage.html" rel="nofollow noreferrer">https://cran.r-project.org/web/packages/shinybusy/vignettes/shinybusy-usage.html</a></p>