Thread safe disctionary and using -parallel switch with foreach in powershell

foreach-concurrentdict.ps1

# summary of code covered here: https://isc.sans.edu/diary/Port%20Scanning%20in%20Powershell%20Redux%3A%20Speeding%20Up%20the%20Results%20%28challenge%20accepted!%29/29324

$gkeclusters = [System.Collections.Concurrent.ConcurrentDictionary[string,object]]::new()

$gcpprojects.projectId | % -ThrottleLimit 10 -Parallel {
   write-host "checking $($_)"
   $dict = $using:gkeclusters
   $dict.TryAdd($(gcloud container clusters list --project $_ --format json), $_) | out-null
}