Unread mail badge on iPhone app should update/disappear when I read emails on my MacBook.

To me this is a functional flaw. If I'm working on my MacBook and read an email, I don't want to have to open the mail app on my iPhone for the unread email notification badge to go away. It should automatically update. I admit, I'm very particular about "getting to zero," but often it's such a waste of time for me because I'll read emails on my MacBook, then a bit later I pic up my iPhone, see the unread email notification, and open the app... only to realize that these are emails I have already read on my MacBook.