I didn't downvote you, but thought it'd be better to make it clear what the person was referring to. The scenario mentioned was chatting with customer service on a website (like chatting with Apple customer care on Apple's website, foe example), where any message you type or edit would be seen by the customer service agent while you type, even if you didn't hit Enter or click on Send. This is not related in any way to the autocomplete feature on Apple's iOS keyboard or about what third party keyboards on iOS can do.
