Get-Mailbox Progress Bar

Good Evening,

I am using Powershell Studio and I have a progress bar control on my form, I use the following command to get all of our mailboxes in our Office 365 tenant:

Get-Mailbox -Resultsize Unlimited

The trouble is, this command takes a while to run, how can I use the progress bar control to measure the time it takes this command to run?

Thanks for any help.