Function turn_wire 

fn turn_wire(
    messages: &[Message],
    from: usize,
    to: usize,
    key: Option<&str>,
    endings: &HashMap<String, TaskEnding>,
) -> TurnWire

The messages from..to as one turn, which is the shape both the session record and a page carry.

A task ending a call in this turn is owed rides along. A client folds one turn at a time, so an ending the CLI persisted in another turn is one it cannot reach - and the notice opens a turn of its own, which puts it in another turn whenever anything that does open one sits between. The row the CLI wrote stays where it is and draws nothing; what is added is a frame of its own, which is content of the wire’s own type rather than a second copy of a drawing.