Is your feature request related to a problem? Please describe.

I cannot tell azure storage copy to limit the transfer rate, which is causing an overload on my compute resource's 1Gb external link, causing symptoms not unlike a DDOS attack.

Describe the solution you'd like

Somehow make --cap-mbps option available from azure storage copy call.

Describe alternatives you've considered

I have spent a while trying to install and successfully log into azcopy so that I can make use of its --cap-mbps option, which has itself required its own troubleshooting on this system and I have so far been unsuccessful with. I've tried several of the options on this wiki: https://github.com/Azure/azure-storage-azcopy/wiki/Improved-login-support-for-AzCopy-commands-(with-in-memory-secret-store) to help with my login troubles. I was linked there by issue #193, which is closed, but mentions the same error message that I repeatedly get.

Additional context