C function cli_progress_sleep() is used in an example but not documented.

[krivit]

In the following example, it's not clear what it does; is it meant to be a placeholder for the actual computation, or does it serve a function?

cli/vignettes/progress-advanced.Rmd

Lines 462 to 473 in 3dd94c0

	#include <cli/progress.h>
	SEXP progress_test1() {
	int i;
	SEXP bar = PROTECT(cli_progress_bar(1000, NULL));
	for (i = 0; i < 1000; i++) {
	cli_progress_sleep(0, 4 * 1000 * 1000);
	if (CLI_SHOULD_TICK) cli_progress_set(bar, i);
	}
	cli_progress_done(bar);
	UNPROTECT(1);
	return Rf_ScalarInteger(i);
	}