Delayed execution in R Shiny app

Question

Is it possible have some parts of RShiny app execute in a delayed fashion much like the Delayed start in Windows Services?

Let me elaborate.

I have a shiny app

Answer 1

shinyServer(function(input, output, session) {
  values <- reactiveValues(starting = TRUE)
  session$onFlushed(function() {
    values$starting <- FALSE
  })

  output$fast <- renderText({ "This happens right away" })
  output$slow <- renderText({
    if (values$starting)
      return(NULL)
    "This happens later"
  })
})