This is a simplified progress bar, a single (dynamic) message, without progress units.
cli_progress_step(
  msg,
  msg_done = msg,
  msg_failed = msg,
  spinner = FALSE,
  class = if (!spinner) ".alert-info",
  current = TRUE,
  .auto_close = TRUE,
  .envir = parent.frame(),
  ...
)Message to show. It may contain glue substitution and cli
styling. It can be updated via cli_progress_update(), as usual.
It is style as a cli info alert (see cli_alert_info()).
Message to show on successful termination. By default
this it is the same as msg and it is styled as a cli success alert
(see cli_alert_success()).
Message to show on unsuccessful termination. By
default it is the same as msg and it is styled as a cli danger alert
(see cli_alert_danger()).
Whether to show a spinner at the beginning of the line.
To make the spinner spin, you'll need to call cli_progress_update()
regularly.
cli class to add to the message. By default there is no class for steps with a spinner.
Passed to cli_progress_bar().
Passed to cli_progress_bar().
Passed to cli_progress_bar().
Passed to cli_progress_bar().
cli_progress_step() always shows the progress message,
even if no update is due.
f <- function() {
  cli_progress_step("Downloading data")
  Sys.sleep(2)
  cli_progress_step("Importing data")
  Sys.sleep(1)
  cli_progress_step("Cleaning data")
  Sys.sleep(2)
  cli_progress_step("Fitting model")
  Sys.sleep(3)
}
f()
You can add a spinner to some or all steps with spinner = TRUE,
but note that this will only work if you call cli_progress_update()
regularly.
f <- function() {
  cli_progress_step("Downloading data", spinner = TRUE)
  for (i in 1:100) { Sys.sleep(2/100); cli_progress_update() }
  cli_progress_step("Importing data")
  Sys.sleep(1)
  cli_progress_step("Cleaning data")
  Sys.sleep(2)
  cli_progress_step("Fitting model", spinner = TRUE)
  for (i in 1:100) { Sys.sleep(3/100); cli_progress_update() }
}
f()
You can make the step messages dynamic, using glue templates.
Since cli_progress_step() show that message immediately, we need
to initialize msg first.
f <- function() {
  msg <- ""
  cli_progress_step("Downloading data{msg}", spinner = TRUE)
  for (i in 1:100) {
    Sys.sleep(2/100)
    msg <- glue::glue(", got file {i}/100")
    cli_progress_update()
  }
  cli_progress_step("Importing data")
  Sys.sleep(1)
  cli_progress_step("Cleaning data")
  Sys.sleep(2)
  cli_progress_step("Fitting model", spinner = TRUE)
  for (i in 1:100) { Sys.sleep(3/100); cli_progress_update() }
}
f()
You can specify a different message for successful and/or unsuccessful termination:
f <- function() {
  size <- 0L
  cli_progress_step(
    "Downloading data.",
    msg_done = "Downloaded {prettyunits::pretty_bytes(size)}.",
    spinner = TRUE
  )
  for (i in 1:100) {
    Sys.sleep(3/100)
    size <- size + 8192
    cli_progress_update()
  }
}
f()
This function supports inline markup.
Other progress bar functions: 
cli_progress_along(),
cli_progress_bar(),
cli_progress_builtin_handlers(),
cli_progress_message(),
cli_progress_num(),
cli_progress_output(),
cli_progress_styles(),
progress-variables
Other functions supporting inline markup: 
cli_abort(),
cli_alert(),
cli_blockquote(),
cli_bullets_raw(),
cli_bullets(),
cli_dl(),
cli_h1(),
cli_li(),
cli_ol(),
cli_process_start(),
cli_progress_along(),
cli_progress_bar(),
cli_progress_message(),
cli_progress_output(),
cli_rule,
cli_status_update(),
cli_status(),
cli_text(),
cli_ul(),
format_error(),
format_inline()