Function prepare 

pub fn prepare<G: GameData>(
    start: Start<G>,
    record: &SessionRecord,
    stamps: Stamps,
) -> Result<(Start<G>, Vec<String>), SessionError>

start made ready to play record: a record of another version refused, the record’s stamp checked against the start’s as stamps says, and the record’s voice manifest put in its setup. Beside it, what the playback can’t promise, one line each.