I think it's kind of funny how Google is using this as an example when their own Gmail app in iOS has the "Write a new email" action as a floating action button with a pencil and the word "Compose".

I wish they labeled all the major FABs. It took me ages to figure out how to make a new spreadsheet in Google Sheets on the desktop after they switched to a mobile-first UI. That Google-logo-colored "+" button in the lower right is not easy to see. If it had text next to it I'm sure it would have been harder to overlook.