Testing Async calls to Office 365

AsyncMailbox.ps1

$PowerShell = [powershell]::Create()
    
$null = $PowerShell.AddScript({
    param($Credential)

    $ExchParams = @{
      ConfigurationName = 'microsoft.exchange'
      ConnectionUri = "https://outlook.office365.com/powershell-liveid/"
      Credential = $Credential
      Authentication = 'Basic'
      AllowRedirection = $true
    }
    $ExchSession = New-PSSession @ExchParams
    Import-PSSession -Session $ExchSession

    Get-Mailbox Matt
    }).AddArgument($Cred)
    
$Handle = $PowerShell.BeginInvoke()
$PowerShell.EndInvoke($Handle)
$PowerShell.Dispose()