I’d like to request an opt-in feature for file transfers. I’ve occasionally sent the wrong document to a recipient using this function. It works too well!
It would help to have a pause function, where it asks “is this the document you mean to send?” (there is no need to confirm the recipient, as transfer is taking place during a live session, and you are choosing to send it to the person with whom you are speaking). It just needs to confirm the document.
Another solution: the ability to immediately recall the document, if you figure out quickly that you pressed the wrong button.