Struct TurnSpan 

pub struct TurnSpan {
    pub opens_at: usize,
    pub key: Option<String>,
}

Where one turn sits in the conversation it was folded from, and what names it.

In MESSAGE terms, because a page crosses as whole turns: a client is handed each turn’s messages and folds them itself, so the boundary a page is cut on has to name a message.

Fields

opens_at: usize

The message the turn opens at.

key: Option<String>

The key the fold named the turn by, None when nothing did - a conversation read from a transcript carries no Result frame, and the key comes from one.