SpecifiedPickupDirectory Implementation

[DaleCam]

Hi there! Thank you so much for your work here!
I was just wondering if you could implement the Smtp Specified Pickup Directory option based on the answer here by the mailkit guy himself:
https://stackoverflow.com/questions/39930103/sending-email-to-specifiedpickupdirectory-with-mailkit

I know its not a default mailkit setting, but it would help with compatability with the previous System.Net.Mail implementations.
Thanks regardless of your answer!