How to show a progressBar in a single function in shiny?

Here is an example. The progress bar just jumps from 0% to 100% due a single function getres(). How to indicate the progress smoothly?

library("shiny")
library("shinyWidgets")
library("DESeq2")
library("airway")
data(airway)

getres <- function(eset){
  dds<-DESeqDataSet(eset, design = ~cell + dex)
  keep <- rowSums(counts(dds)) >= 10
  dds <- dds[keep,]
  dds <- DESeq(dds)
  res <- results(dds)
  return(res) 
}


ui <- fluidPage(
  tags$h1("Progress bar in Sweet Alert"),
  useSweetAlert(), # /!\ needed with 'progressSweetAlert'
  actionButton(
    inputId = "go",
    label = "Launch long calculation !"
  )
)

server <- function(input, output, session) {

  observeEvent(input$go, {
    progressSweetAlert(
      session = session, id = "myprogress",
      title = "Work in progress",
      display_pct = TRUE, value = 0
    )
    for (i in seq_len(1)) {
      Sys.sleep(0.1)
      updateProgressBar(
        session = session,
        id = "myprogress",
        res<-getres(airway),
        value = i
      )
    }
    closeSweetAlert(session = session)
    sendSweetAlert(
      session = session,
      title =" Calculation completed !",
      type = "success"
    )
  })

}

shinyApp(ui = ui, server = server)