A powershell sleep function with progress bar, which is precise(no cumulative error), not affected by system clock, and highly readable.

Start-Sleep-With-Progress.ps1

function Start-Sleep-With-Progress {
    param (
        [string]$Activity,
        [int]$Seconds
    )

    $duration = New-TimeSpan -Seconds $Seconds

    $stopwatch = [System.Diagnostics.Stopwatch]::StartNew()

    while ($stopWatch.Elapsed -lt $duration) {
        $elapsed = $stopWatch.Elapsed
        $remaining = [TimeSpan]::FromTicks([math]::Max(($duration - $elapsed).Ticks, 0))
        $percent = ($elapsed.TotalMilliseconds / $duration.TotalMilliseconds) * 100

        $progressText = "$((New-TimeSpan -Seconds $elapsed.TotalSeconds).ToString("c")) / $((New-TimeSpan -Seconds $duration.TotalSeconds).ToString("c"))"
        Write-Progress `
            -Activity "$Activity" `
            -CurrentOperation "Sleeping" `
            -Status $progressText `
            -PercentComplete $percent `
            -SecondsRemaining $remaining.TotalSeconds

        Start-Sleep -Milliseconds $([math]::Min(50.0, $remaining.TotalMilliseconds))
    }

    $stopWatch.Stop()
    Write-Progress -Activity "$Activity" -Completed
}