获取Powershell循环中当前项的索引？

foreach ($server in $servers) {
    Write-Host "Processing server $server" -ForegroundColor Green
    $i = 0
    foreach ($volume in $server.Disks) {
        Write-Host "  Processing disk $($volume.Name) ($($volume.Number))" -ForegroundColor Green
        $i++
    }
}