How to use SplitPipeline with o365 cmdlets - powershell

Question

I have been trying to check the mailboxes for a specific list of users (about 14k users) because it is possible that a malicious rule has been created.
I created a very simple PowerShell script to achieve that but obviously it took more than 12 hours to finish. I have found a multi-threading option to process all this data: SplitPipeline, but I don't even know how to start.
After installing and importing the module and logging into O365, I'm trying this (please not that I'm just starting in this powershell world, I'm not an expert):
$file = Get-Content userlist.txt
$outputFile = "outputFile.txt"
$data = #{
Count = $file.Count
Done = 0
}
$file | Split-Pipeline -Count 10 -Variable data {process{
[System.Threading.Monitor]::Enter($data)
try
{
$done = ++$data.Done
}
finally
{
[System.Threading.Monitor]::Exit($data)
}
Write-Progress -Activity "Done $done" -Status Processing -PercentComplete (100*$done/$data.Count)
$User2Check = $_
Write-Host "Checking $User2Check"
get-mailbox $User2Check | Select identity
}} | Set-Content $outputFile
The result is the typical message: The term 'get-mailbox' is not recognized as the name of a cmdlet, it is like SplitPipeline is not aware I'm logged against O365.
Do you have any ideas?

Answer 1

You have to understand how Split-Pipeline works, it runs in its own workspace. Unfortunately one cannot call/use functions and variables specified outside split-pipeline run space. You can use the -Variable -Function switches provided by Split-pipeline, but keep in mind that in the case of functions, any global variable used by xyz function you are trying to call cannot see the global variable.
Indoor case, get-mailbox is null because Split-pipe does not know about it, you will have to include the model and create a new connection to office in order for the get-mailbox cmdlet to work.