In Walkie Talkie, with Record, then send chosen, letting go of the Talk button now sends the message. For the next 3 seconds the line above the Talk button says it is about to be sent and offers Undo; pressing Talk again sends it at once. To cancel while you are still holding, slide away from the button and let go, or press Escape while you hold the space bar.
A recording you lock on by sliding up, or start with Enter or Tap to talk, still waits when you stop, for you to play it back, Send it or Delete it.
The top of a conversation also takes less room.