Let Others Know When Uploading a File

It is a known feature to everyone that when someone is typing a message, "Username is typing..." appears.However, what about when uploading a file?

Your best friend is waiting for a reply after they've asked twenty questions about Wumpus and your file is still uploading! What do they do? "@Username, @Username, @Username!"

How about a feature to let others know when you're uploading a file! That should solve the problem, except now they'll ask why your internet's so slow... "Username is uploading a file..."