shawnmclean/Mandrill-dotnet — pull request #65 by luke-at-work (2014-04-09 09:50:06+00:00)
Title: add support for return_path_domain message param

Enables setting of a custom return path domain on a per-message basis.

http://help.mandrill.com/entries/25241243-Can-I-customize-the-Return-Path-bounce-address-used-for-my-emails-
https://mandrillapp.com/api/docs/messages.JSON.html