progressr.R

library(future)
library(progressr)
library(furrr)

# 2 cores
plan(multisession, workers = 2L)

x <- 1:20

random_sleep <- function() {
  Sys.sleep(sample(1:3, size = 1L))
}

with_progress({
  # Create a progressor
  p <- progressor(along = x)
  
  future_map(x, ~{
    # Sleep for a random amount of time
    random_sleep()
    
    # Tick the progress bar
    p()
  })
})

# shut down the workers
plan(sequential)

Minor: To shut down workers, you need to switch to another plan - plan(sequential) is a good choice. Using plan() will only display the currently set future plan.

Woops! Thanks - updated