Pop-up asking if I'm sure I want to leave the conversation.

Accidentally clicked the back button on my phone while in a conversation, unfortunately by the time I got back into it the time was up. It would be handy to have a pop-up warning me that I'm leaving the conversation and asking if I'm sure I want to leave or if I want to stay. It would also be nice if my partially typed responses were remembered in instances like this. That way I can simply finish it up before a conversation is over.