Show a progress bar on the console. Usage:

// Create a progress bar, and configure the total amount of work that
// needs to be done.
$bar = id(new PhutilConsoleProgressBar())
  ->setTotal(count($stuff));

// As you complete the work, update the progress bar.
foreach ($stuff as $thing) {
  do_stuff($thing);
  $bar->update(1);
}

// When complete, mark the work done to clear the bar.
$bar->done();

The progress bar attempts to account for various special cases, notably:

• If stderr is not a TTY, the bar will not be drawn (for example, if it is being piped to a log file).
• If the Phutil log output is enabled (usually because --trace was specified), the bar will not be drawn.
• The bar will be resized to the width of the console if possible.